diff --git a/addons/hr_holidays/models/hr_leave_allocation.py b/addons/hr_holidays/models/hr_leave_allocation.py
index ba646a589dd..995272f80c6 100644
--- a/addons/hr_holidays/models/hr_leave_allocation.py
+++ b/addons/hr_holidays/models/hr_leave_allocation.py
@@ -66,6 +66,7 @@ class HolidaysAllocation(models.Model):
     employee_id = fields.Many2one(
         'hr.employee', compute='_compute_from_holiday_type', store=True, string='Employee', index=True, readonly=False, ondelete="restrict", tracking=True,
         states={'cancel': [('readonly', True)], 'refuse': [('readonly', True)], 'validate1': [('readonly', True)], 'validate': [('readonly', True)]})
+    employee_company_id = fields.Many2one(related='employee_id.company_id', readonly=True)
     active_employee = fields.Boolean('Active Employee', related='employee_id.active', readonly=True)
     manager_id = fields.Many2one('hr.employee', compute='_compute_from_employee_id', store=True, string='Manager')
     notes = fields.Html('Reasons', readonly=True, states={'draft': [('readonly', False)], 'confirm': [('readonly', False)]})
@@ -429,19 +430,25 @@ class HolidaysAllocation(models.Model):
                         date=allocation.holiday_status_id.validity_stop
                     ))
 
-    @api.model
-    def create(self, values):
+    @api.model_create_multi
+    def create(self, vals_list):
         """ Override to avoid automatic logging of creation """
-        employee_id = values.get('employee_id', False)
-        if not values.get('department_id'):
-            values.update({'department_id': self.env['hr.employee'].browse(employee_id).department_id.id})
-        holiday = super(HolidaysAllocation, self.with_context(mail_create_nosubscribe=True)).create(values)
-        holiday.add_follower(employee_id)
-        if holiday.validation_type == 'hr':
-            holiday.message_subscribe(partner_ids=(holiday.employee_id.parent_id.user_id.partner_id | holiday.employee_id.leave_manager_id.partner_id).ids)
-        if not self._context.get('import_file'):
-            holiday.activity_update()
-        return holiday
+        for values in vals_list:
+            employee_id = values.get('employee_id', False)
+            if not values.get('department_id'):
+                values.update({'department_id': self.env['hr.employee'].browse(employee_id).department_id.id})
+        holidays = super(HolidaysAllocation, self.with_context(mail_create_nosubscribe=True)).create(vals_list)
+        for holiday in holidays:
+            partners_to_subscribe = set()
+            if holiday.employee_id.user_id:
+                partners_to_subscribe.add(holiday.employee_id.user_id.partner_id.id)
+            if holiday.validation_type == 'hr':
+                partners_to_subscribe.add(holiday.employee_id.parent_id.user_id.partner_id.id)
+                partners_to_subscribe.add(holiday.employee_id.leave_manager_id.partner_id.id)
+            holiday.message_subscribe(partner_ids=tuple(partners_to_subscribe))
+            if not self._context.get('import_file'):
+                holiday.activity_update()
+        return holidays
 
     def write(self, values):
         employee_id = values.get('employee_id', False)
diff --git a/addons/hr_holidays/views/hr_leave_allocation_views.xml b/addons/hr_holidays/views/hr_leave_allocation_views.xml
index 192f4a70321..aec55755dc9 100644
--- a/addons/hr_holidays/views/hr_leave_allocation_views.xml
+++ b/addons/hr_holidays/views/hr_leave_allocation_views.xml
@@ -100,7 +100,7 @@
                                 <label for="number_of_days" string="Duration" attrs="{'invisible': [('allocation_type', '=', 'accrual')]}"/>
                                 <label for="number_of_days" string="Extra days" attrs="{'invisible': [('allocation_type', '!=', 'accrual')]}"/>
                             </div>
-                            <div>
+                            <div name="duration_display">
                                 <field name="number_of_days_display" class="oe_inline" nolabel="1"
                                     attrs="{'readonly': ['|', ('type_request_unit', '=', 'hour'), ('state', 'not in', ('draft', 'confirm'))], 'invisible': [('type_request_unit', '=', 'hour')]}"/>
                                 <field name="number_of_hours_display" class="oe_inline" nolabel="1"
diff --git a/addons/hr_holidays/views/hr_leave_views.xml b/addons/hr_holidays/views/hr_leave_views.xml
index 1739db22307..0c44d00bbac 100644
--- a/addons/hr_holidays/views/hr_leave_views.xml
+++ b/addons/hr_holidays/views/hr_leave_views.xml
@@ -314,7 +314,7 @@
                         <!-- When the user is leave manager, he should always see `number_of_days` to allow
                         him to edit the value. `number_of_hours_display` is only an informative field -->
                         <label for="number_of_days" string="Duration" attrs="{'invisible': [('request_unit_half', '=', True), ('leave_type_request_unit', '!=', 'hour')]}"/>
-                        <div>
+                        <div name="duration_display">
                             <div class="o_row">
                                 <div groups="!hr_holidays.group_hr_holidays_manager" attrs="{'invisible': ['|', ('request_unit_half', '=', True), ('request_unit_hours', '=', True)]}" class="o_row">
                                     <field name="number_of_days_display" nolabel="1" readonly="1" class="oe_inline"/>
diff --git a/addons/hr_holidays_attendance/__init__.py b/addons/hr_holidays_attendance/__init__.py
index e69de29bb2d..90b17558ffc 100644
--- a/addons/hr_holidays_attendance/__init__.py
+++ b/addons/hr_holidays_attendance/__init__.py
@@ -0,0 +1,5 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from . import models
+from . import tests
diff --git a/addons/hr_holidays_attendance/__manifest__.py b/addons/hr_holidays_attendance/__manifest__.py
index 322a6081147..c3533fad036 100644
--- a/addons/hr_holidays_attendance/__manifest__.py
+++ b/addons/hr_holidays_attendance/__manifest__.py
@@ -1,15 +1,30 @@
 # -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
 {
     'name': "HR Attendance Holidays",
-    'summary': """""",
+    'summary': """Attendance Holidays""",
     'category': 'Human Resources',
     'description': """
-Hides the attendance presence button when an employee is on leave.
+Convert employee's extra hours to leave allocations.
     """,
     'version': '1.0',
     'depends': ['hr_attendance', 'hr_holidays'],
     'auto_install': True,
     'data': [
+        'security/hr_holidays_attendance_security.xml',
+        'views/hr_leave_allocation_views.xml',
+        'views/hr_leave_type_views.xml',
+        'views/hr_leave_views.xml',
         'views/hr_employee_views.xml',
+        'views/res_users_views.xml',
+        'data/hr_holidays_attendance_data.xml',
     ],
+    'demo': [
+        'data/hr_holidays_attendance_demo.xml',
+    ],
+    'assets': {
+        'web.assets_qweb': [
+            'hr_holidays_attendance/static/src/xml/time_off_calendar.xml',
+        ],
+    },
 }
diff --git a/addons/hr_holidays_attendance/data/hr_holidays_attendance_data.xml b/addons/hr_holidays_attendance/data/hr_holidays_attendance_data.xml
new file mode 100644
index 00000000000..963a07053fa
--- /dev/null
+++ b/addons/hr_holidays_attendance/data/hr_holidays_attendance_data.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<odoo>
+    <data noupdate="1">
+        <record id="holiday_status_extra_hours" model="hr.leave.type">
+            <field name="name">Extra Hours</field>
+            <field name="request_unit">hour</field>
+            <field name="allocation_type">no</field>
+            <field name="leave_validation_type">manager</field>
+            <field name="overtime_deductible" eval="True"/>
+            <field name="active" eval="False"/>
+            <field name="company_id" eval="False"/>
+        </record>
+    </data>
+</odoo>
diff --git a/addons/hr_holidays_attendance/data/hr_holidays_attendance_demo.xml b/addons/hr_holidays_attendance/data/hr_holidays_attendance_demo.xml
new file mode 100644
index 00000000000..6d6ffa73ee4
--- /dev/null
+++ b/addons/hr_holidays_attendance/data/hr_holidays_attendance_demo.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<odoo>
+    <data noupdate="1">
+        <record id="base.main_company" model="res.company">
+            <field name="hr_attendance_overtime" eval="True" />
+            <field name="overtime_start_date" eval="(DateTime.today() + relativedelta(months=-1)).date()" />
+        </record>
+    </data>
+</odoo>
diff --git a/addons/hr_holidays_attendance/models/__init__.py b/addons/hr_holidays_attendance/models/__init__.py
new file mode 100644
index 00000000000..a55416cd161
--- /dev/null
+++ b/addons/hr_holidays_attendance/models/__init__.py
@@ -0,0 +1,8 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from . import hr_leave_allocation
+from . import hr_leave_type
+from . import hr_leave
+from . import res_company
+from . import res_users
diff --git a/addons/hr_holidays_attendance/models/hr_leave.py b/addons/hr_holidays_attendance/models/hr_leave.py
new file mode 100644
index 00000000000..7c34d74caf7
--- /dev/null
+++ b/addons/hr_holidays_attendance/models/hr_leave.py
@@ -0,0 +1,81 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import api, fields, models, _
+from odoo.exceptions import ValidationError
+from odoo.tools import float_round
+
+
+class HRLeave(models.Model):
+    _inherit = 'hr.leave'
+
+    overtime_id = fields.Many2one('hr.attendance.overtime', string='Extra Hours', groups='hr_holidays.group_hr_holidays_user')
+    employee_overtime = fields.Float(related='employee_id.total_overtime')
+    overtime_deductible = fields.Boolean(compute='_compute_overtime_deductible')
+
+    @api.depends('holiday_status_id')
+    def _compute_overtime_deductible(self):
+        for leave in self:
+            leave.overtime_deductible = leave.holiday_status_id.overtime_deductible and leave.holiday_status_id.allocation_type == 'no'
+
+    @api.model_create_multi
+    def create(self, vals_list):
+        res = super().create(vals_list)
+        today = fields.Date.today()
+        for leave in res:
+            if not leave.overtime_deductible:
+                continue
+            employee = leave.employee_id.sudo()
+            duration = leave.number_of_hours_display
+            if duration > employee.total_overtime:
+                if employee.user_id == self.env.user:
+                    raise ValidationError(_('You do not have enough extra hours to request this leave'))
+                raise ValidationError(_('The employee does not have enough extra hours to request this leave.'))
+            if not leave.overtime_id:
+                leave.sudo().overtime_id = self.env['hr.attendance.overtime'].sudo().create({
+                    'employee_id': employee.id,
+                    'date': today,
+                    'adjustment': True,
+                    'duration': -1 * duration,
+                })
+        return res
+
+    def write(self, vals):
+        res = super().write(vals)
+        fields_to_check = {'number_of_days', 'date_from', 'date_to', 'state', 'employee_id'}
+        if not any(field for field in fields_to_check if field in vals):
+            return res
+        #User may not have access to overtime_id field
+        for leave in self.sudo().filtered('overtime_id'):
+            employee = leave.employee_id
+            duration = leave.number_of_hours_display
+            overtime_duration = leave.overtime_id.sudo().duration
+            if overtime_duration != duration:
+                if duration > employee.total_overtime - overtime_duration:
+                    raise ValidationError(_('The employee does not have enough extra hours to extend this leave.'))
+                leave.overtime_id.sudo().duration = -1 * duration
+        return res
+
+    def action_draft(self):
+        overtime_leaves = self.filtered('overtime_deductible')
+        if any([l.employee_overtime < float_round(l.number_of_hours_display, 2) for l in overtime_leaves]):
+            if self.employee_id.user_id.id == self.env.user.id:
+                raise ValidationError(_('You do not have enough extra hours to request this leave'))
+            raise ValidationError(_('The employee does not have enough extra hours to request this leave.'))
+
+        res = super().action_draft()
+        overtime_leaves.overtime_id.sudo().unlink()
+        for leave in overtime_leaves:
+            overtime = self.env['hr.attendance.overtime'].sudo().create({
+                'employee_id': leave.employee_id.id,
+                'date': fields.Date.today(),
+                'adjustment': True,
+                'duration': -1 * leave.number_of_hours_display
+            })
+            leave.sudo().overtime_id = overtime.id
+        return res
+
+    def action_refuse(self):
+        res = super().action_refuse()
+        self.overtime_id.sudo().unlink()
+        return res
diff --git a/addons/hr_holidays_attendance/models/hr_leave_allocation.py b/addons/hr_holidays_attendance/models/hr_leave_allocation.py
new file mode 100644
index 00000000000..7a87d3bb868
--- /dev/null
+++ b/addons/hr_holidays_attendance/models/hr_leave_allocation.py
@@ -0,0 +1,83 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import api, fields, models, _
+from odoo.exceptions import ValidationError
+from odoo.tools import float_round
+
+
+class HolidaysAllocation(models.Model):
+    _inherit = 'hr.leave.allocation'
+
+    def default_get(self, fields):
+        res = super().default_get(fields)
+        if 'holiday_status_id' in fields and self.env.context.get('deduct_extra_hours'):
+            leave_type = self.env['hr.leave.type'].search([
+                ('valid', '=', True),
+                ('overtime_deductible', '=', True),
+                ('allocation_type', '!=', 'no')], limit=1)
+            res['holiday_status_id'] = leave_type.id
+        return res
+
+    overtime_deductible = fields.Boolean(compute='_compute_overtime_deductible')
+    overtime_id = fields.Many2one('hr.attendance.overtime', string='Extra Hours', groups='hr_holidays.group_hr_holidays_user')
+    employee_overtime = fields.Float(related='employee_id.total_overtime')
+    hr_attendance_overtime = fields.Boolean(related='employee_company_id.hr_attendance_overtime')
+
+    @api.depends('holiday_status_id')
+    def _compute_overtime_deductible(self):
+        for allocation in self:
+            allocation.overtime_deductible = allocation.holiday_status_id.company_id.hr_attendance_overtime and allocation.holiday_status_id.overtime_deductible
+
+    @api.model_create_multi
+    def create(self, vals_list):
+        res = super().create(vals_list)
+        for allocation in res:
+            if allocation.overtime_deductible and allocation.holiday_type == 'employee':
+                duration = allocation.number_of_hours_display
+                if duration > allocation.employee_id.total_overtime:
+                    raise ValidationError(_('The employee does not have enough overtime hours to request this leave.'))
+                if not allocation.overtime_id:
+                    allocation.sudo().overtime_id = self.env['hr.attendance.overtime'].sudo().create({
+                        'employee_id': allocation.employee_id.id,
+                        'date': fields.Date.today(),
+                        'adjustment': True,
+                        'duration': -1 * duration,
+                    })
+        return res
+
+    def write(self, vals):
+        res = super().write(vals)
+        if 'number_of_days' not in vals:
+            return res
+        for allocation in self.filtered('overtime_id'):
+            employee = allocation.employee_id
+            duration = allocation.number_of_hours_display
+            overtime_duration = allocation.overtime_id.sudo().duration
+            if overtime_duration != duration:
+                if duration > employee.total_overtime - overtime_duration:
+                    raise ValidationError(_('The employee does not have enough extra hours to extend this allocation.'))
+                allocation.overtime_id.sudo().duration = -1 * duration
+        return res
+
+    def action_draft(self):
+        overtime_allocations = self.filtered('overtime_deductible')
+        if any([a.employee_overtime < float_round(a.number_of_hours_display, 2) for a in overtime_allocations]):
+            raise ValidationError(_('The employee does not have enough extra hours to request this allocation.'))
+        res = super().action_draft()
+
+        overtime_allocations.overtime_id.sudo().unlink()
+        for allocation in overtime_allocations:
+            overtime = self.env['hr.attendance.overtime'].sudo().create({
+                'employee_id': allocation.employee_id.id,
+                'date': fields.Date.today(),
+                'adjustment': True,
+                'duration': -1 * allocation.number_of_hours_display
+            })
+            allocation.sudo().overtime_id = overtime.id
+        return res
+
+    def action_refuse(self):
+        res = super().action_refuse()
+        self.overtime_id.sudo().unlink()
+        return res
diff --git a/addons/hr_holidays_attendance/models/hr_leave_type.py b/addons/hr_holidays_attendance/models/hr_leave_type.py
new file mode 100644
index 00000000000..ea6b5accac5
--- /dev/null
+++ b/addons/hr_holidays_attendance/models/hr_leave_type.py
@@ -0,0 +1,32 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import fields, models
+
+
+class HRLeaveType(models.Model):
+    _inherit = 'hr.leave.type'
+
+    hr_attendance_overtime = fields.Boolean(related='company_id.hr_attendance_overtime')
+    overtime_deductible = fields.Boolean(
+        "Deduct Extra Hours", default=False,
+        help="Once a time off of this type is approved, extra hours in attendances will be deducted.")
+
+    def get_employees_days(self, employee_ids):
+        res = super().get_employees_days(employee_ids)
+        deductible_time_off_type_ids = self.env['hr.leave.type'].search([
+            ('overtime_deductible', '=', True),
+            ('allocation_type', '=', 'no')]).ids
+        for employee_id, allocations in res.items():
+            for allocation_id in allocations:
+                if allocation_id in deductible_time_off_type_ids:
+                    res[employee_id][allocation_id]['virtual_remaining_leaves'] = self.env['hr.employee'].sudo().browse(employee_id).total_overtime
+                    res[employee_id][allocation_id]['overtime_deductible'] = True
+                else:
+                    res[employee_id][allocation_id]['overtime_deductible'] = False
+        return res
+
+    def _get_days_request(self):
+        res = super()._get_days_request()
+        res[1]['overtime_deductible'] = self.overtime_deductible
+        return res
diff --git a/addons/hr_holidays_attendance/models/res_company.py b/addons/hr_holidays_attendance/models/res_company.py
new file mode 100644
index 00000000000..1e13e416b15
--- /dev/null
+++ b/addons/hr_holidays_attendance/models/res_company.py
@@ -0,0 +1,24 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import models
+
+
+class ResCompany(models.Model):
+    _inherit = 'res.company'
+
+    def write(self, vals):
+        res = super().write(vals)
+        if 'hr_attendance_overtime' not in vals:
+            return res
+        extra_hours_time_off_type = self.env.ref('hr_holidays_attendance.holiday_status_extra_hours', raise_if_not_found=False)
+        if not extra_hours_time_off_type:
+            return res
+        all_companies = self.env['res.company'].sudo().search([])
+        # Unarchive time of type if the feature is enabled
+        if any(company.hr_attendance_overtime and not extra_hours_time_off_type.active for company in all_companies):
+            extra_hours_time_off_type.toggle_active()
+        # Archive time of type if the feature is disabled for all the company
+        if all(not company.hr_attendance_overtime and extra_hours_time_off_type.active for company in all_companies):
+            extra_hours_time_off_type.toggle_active()
+        return res
diff --git a/addons/hr_holidays_attendance/models/res_users.py b/addons/hr_holidays_attendance/models/res_users.py
new file mode 100644
index 00000000000..9267827d3a9
--- /dev/null
+++ b/addons/hr_holidays_attendance/models/res_users.py
@@ -0,0 +1,32 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import api, fields, models
+
+
+class ResUsers(models.Model):
+    _inherit = 'res.users'
+
+    request_overtime = fields.Boolean(compute='_compute_request_overtime')
+
+    @property
+    def SELF_READABLE_FIELDS(self):
+        return super().SELF_READABLE_FIELDS + ['request_overtime']
+
+    @api.depends_context('uid')
+    @api.depends('total_overtime')
+    def _compute_request_overtime(self):
+        is_holiday_user = self.env.user.has_group('hr_holidays.group_hr_holidays_user')
+        time_off_types = self.env['hr.leave.type'].search_count([
+            ('valid', '=', True),
+            ('allocation_type', '=', 'fixed_allocation'),
+            ('overtime_deductible', '=', True)
+        ])
+        for user in self:
+            if user.total_overtime >= 1:
+                if is_holiday_user:
+                    user.request_overtime = True
+                else:
+                    user.request_overtime = time_off_types
+            else:
+                user.request_overtime = False
diff --git a/addons/hr_holidays_attendance/security/hr_holidays_attendance_security.xml b/addons/hr_holidays_attendance/security/hr_holidays_attendance_security.xml
new file mode 100644
index 00000000000..f96b3771553
--- /dev/null
+++ b/addons/hr_holidays_attendance/security/hr_holidays_attendance_security.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<odoo>
+    <record id="hr_holidays.group_hr_holidays_user" model="res.groups">
+        <field name="implied_ids" eval="[(4, ref('hr_attendance.group_hr_attendance_user'))]"/>
+    </record>
+</odoo>
diff --git a/addons/hr_holidays_attendance/static/src/xml/time_off_calendar.xml b/addons/hr_holidays_attendance/static/src/xml/time_off_calendar.xml
new file mode 100644
index 00000000000..dc9bfb8f81d
--- /dev/null
+++ b/addons/hr_holidays_attendance/static/src/xml/time_off_calendar.xml
@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<templates id="template" xml:space="preserve">
+    <t t-inherit="hr_holidays.dashboard_calendar_header" t-inherit-mode="extension">
+        <!--inject a first condition-->
+        <xpath expr="//t[@t-if='need_allocation']" position="before">
+            <t t-if="timeoff[1]['overtime_deductible'] == true &amp;&amp; !need_allocation">
+                <span t-esc="timeoff[1]['virtual_remaining_leaves']" class="o_timeoff_big o_timeoff_green font-weight-bold"/> Hours <span class="o_timeoff_green">Available </span>
+            </t>
+        </xpath>
+        <!--change t-if to t-elif-->
+        <xpath expr="//t[@t-if='need_allocation']" position="attributes">
+            <attribute name="t-if"/>
+            <attribute name="t-elif">need_allocation</attribute>
+        </xpath>
+    </t>
+    <t t-inherit="hr_holidays.dashboard_calendar_header_mobile" t-inherit-mode="extension">
+        <!--inject a first condition-->
+        <xpath expr="//t[@t-if='need_allocation']" position="before">
+            <t t-if="timeoff[1]['overtime_deductible'] == true &amp;&amp; !need_allocation">
+                <strong t-esc="timeoff[1]['virtual_remaining_leaves']" class="o_timeoff_green"/> Hours <span class="o_timeoff_green ml-2">Available </span>
+            </t>
+        </xpath>
+        <!--change t-if to t-elif-->
+        <xpath expr="//t[@t-if='need_allocation']" position="attributes">
+            <attribute name="t-if"/>
+            <attribute name="t-elif">need_allocation</attribute>
+        </xpath>
+    </t>
+</templates>
diff --git a/addons/hr_holidays_attendance/tests/__init__.py b/addons/hr_holidays_attendance/tests/__init__.py
new file mode 100644
index 00000000000..0bb87260a2c
--- /dev/null
+++ b/addons/hr_holidays_attendance/tests/__init__.py
@@ -0,0 +1,4 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from . import test_holidays_overtime
diff --git a/addons/hr_holidays_attendance/tests/test_holidays_overtime.py b/addons/hr_holidays_attendance/tests/test_holidays_overtime.py
new file mode 100644
index 00000000000..448bd1b3392
--- /dev/null
+++ b/addons/hr_holidays_attendance/tests/test_holidays_overtime.py
@@ -0,0 +1,216 @@
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from datetime import datetime
+
+from odoo.tests import new_test_user
+from odoo.tests.common import TransactionCase, tagged
+
+from odoo.exceptions import AccessError, ValidationError
+
+@tagged('post_install', '-at_install', 'holidays_attendance')
+class TestHolidaysOvertime(TransactionCase):
+
+    def setUp(self):
+        super().setUp()
+        self.company = self.env['res.company'].create({
+            'name': 'SweatChipChop Inc.',
+            'hr_attendance_overtime': True,
+            'overtime_start_date': datetime(2021, 1, 1)
+        })
+        self.env.company = self.company
+        self.user = new_test_user(self.env, login='user', groups='base.group_user,hr_attendance.group_hr_attendance', company_id=self.company.id)
+        self.user_manager = new_test_user(self.env, login='manager', groups='base.group_user,hr_holidays.group_hr_holidays_user', company_id=self.company.id)
+
+        self.manager = self.env['hr.employee'].create({
+            'name': 'Dominique',
+            'user_id': self.user_manager.id,
+            'company_id': self.company.id,
+        })
+        self.employee = self.env['hr.employee'].create({
+            'name': 'Barnabé',
+            'user_id': self.user.id,
+            'parent_id': self.manager.id,
+            'company_id': self.company.id,
+        })
+
+        self.leave_type_no_alloc = self.env['hr.leave.type'].create({
+            'name': 'Overtime Compensation No Allocation',
+            'company_id': self.company.id,
+            'allocation_type': 'no',
+            'overtime_deductible': True,
+        })
+        self.leave_type_employee_allocation = self.env['hr.leave.type'].create({
+            'name': 'Overtime Compensation Employee Allocation',
+            'company_id': self.company.id,
+            'allocation_type': 'fixed_allocation',
+            'overtime_deductible': True,
+        })
+        self.leave_type_manager_alloc = self.env['hr.leave.type'].create({
+            'name': 'Overtime Compensation Manager Allocation',
+            'company_id': self.company.id,
+            'allocation_type': 'fixed',
+            'overtime_deductible': True,
+        })
+
+    def new_attendance(self, check_in, check_out=False):
+        return self.env['hr.attendance'].create({
+            'employee_id': self.employee.id,
+            'check_in': check_in,
+            'check_out': check_out,
+        })
+
+    def test_deduct_button_visibility(self):
+        with self.with_user('user'):
+            self.assertFalse(self.user.request_overtime, 'Button should not be visible')
+
+            self.new_attendance(check_in=datetime(2021, 1, 2, 8), check_out=datetime(2021, 1, 2, 18))
+            self.assertEqual(self.user.total_overtime, 10, 'Should have 10 hours of overtime')
+            self.assertTrue(self.user.request_overtime, 'Button should be visible')
+
+    def test_check_overtime(self):
+        with self.with_user('user'):
+            self.assertEqual(self.user.total_overtime, 0, 'No overtime')
+
+            with self.assertRaises(ValidationError), self.cr.savepoint():
+                self.env['hr.leave'].create({
+                    'name': 'no overtime',
+                    'employee_id': self.employee.id,
+                    'holiday_status_id': self.leave_type_no_alloc.id,
+                    'number_of_days': 1,
+                    'date_from': datetime(2021, 1, 4),
+                    'date_to': datetime(2021, 1, 5),
+                    'state': 'draft',
+                })
+
+            self.new_attendance(check_in=datetime(2021, 1, 2, 8), check_out=datetime(2021, 1, 2, 16))
+            self.assertEqual(self.employee.total_overtime, 8, 'Should have 8 hours of overtime')
+            leave = self.env['hr.leave'].create({
+                'name': 'no overtime',
+                'employee_id': self.employee.id,
+                'holiday_status_id': self.leave_type_no_alloc.id,
+                'number_of_days': 1,
+                'date_from': datetime(2021, 1, 4),
+                'date_to': datetime(2021, 1, 5),
+            })
+
+            # The employee doesn't have the right to read the overtime from the leave
+            overtime = leave.sudo().overtime_id.with_user(self.user)
+
+            # An employee cannot delete an overtime adjustment
+            with self.assertRaises(AccessError), self.cr.savepoint():
+                overtime.unlink()
+
+            # ... nor change its duration
+            with self.assertRaises(AccessError), self.cr.savepoint():
+                overtime.duration = 8
+
+    def test_leave_adjust_overtime(self):
+        self.new_attendance(check_in=datetime(2021, 1, 2, 8), check_out=datetime(2021, 1, 2, 16))
+        self.assertEqual(self.employee.total_overtime, 8, 'Should have 8 hours of overtime')
+
+        leave = self.env['hr.leave'].create({
+            'name': 'no overtime',
+            'employee_id': self.employee.id,
+            'holiday_status_id': self.leave_type_no_alloc.id,
+            'number_of_days': 1,
+            'date_from': datetime(2021, 1, 4),
+            'date_to': datetime(2021, 1, 5),
+        })
+
+        self.assertTrue(leave.overtime_id.adjustment, "An adjustment overtime should be created")
+        self.assertEqual(leave.overtime_id.duration, -8)
+
+        self.assertEqual(self.employee.total_overtime, 0)
+
+        leave.action_refuse()
+        self.assertFalse(leave.overtime_id.exists(), "Overtime should be deleted")
+        self.assertEqual(self.employee.total_overtime, 8)
+
+        leave.action_draft()
+        self.assertTrue(leave.overtime_id.exists(), "Overtime should be created")
+        self.assertEqual(self.employee.total_overtime, 0)
+
+    def test_leave_check_overtime_write(self):
+        self.new_attendance(check_in=datetime(2021, 1, 2, 8), check_out=datetime(2021, 1, 2, 16))
+        self.new_attendance(check_in=datetime(2021, 1, 3, 8), check_out=datetime(2021, 1, 3, 16))
+        self.assertEqual(self.employee.total_overtime, 16)
+
+        leave = self.env['hr.leave'].create({
+            'name': 'no overtime',
+            'employee_id': self.employee.id,
+            'holiday_status_id': self.leave_type_no_alloc.id,
+            'number_of_days': 1,
+            'date_from': datetime(2021, 1, 4),
+            'date_to': datetime(2021, 1, 5),
+        })
+        self.assertEqual(self.employee.total_overtime, 8)
+
+        leave.date_to = datetime(2021, 1, 6)
+        self.assertEqual(self.employee.total_overtime, 0)
+        with self.assertRaises(ValidationError), self.cr.savepoint():
+            leave.date_to = datetime(2021, 1, 7)
+
+        leave.date_to = datetime(2021, 1, 5)
+        self.assertEqual(self.employee.total_overtime, 8)
+
+    def test_employee_create_allocation(self):
+        with self.with_user('user'):
+            self.assertEqual(self.employee.total_overtime, 0)
+            with self.assertRaises(ValidationError), self.cr.savepoint():
+                self.env['hr.leave.allocation'].create({
+                    'name': 'test allocation',
+                    'holiday_status_id': self.leave_type_employee_allocation.id,
+                    'employee_id': self.employee.id,
+                    'number_of_days': 1,
+                    'state': 'draft',
+                })
+
+            self.new_attendance(check_in=datetime(2021, 1, 2, 8), check_out=datetime(2021, 1, 2, 16))
+            self.assertAlmostEqual(self.employee.total_overtime, 8, 'Should have 8 hours of overtime')
+
+            allocation = self.env['hr.leave.allocation'].create({
+                'name': 'test allocation',
+                'holiday_status_id': self.leave_type_employee_allocation.id,
+                'employee_id': self.employee.id,
+                'number_of_days': 1,
+                'state': 'draft',
+            })
+            allocation.action_confirm()
+            self.assertEqual(self.employee.total_overtime, 0)
+
+            leave_type = self.env['hr.leave.type'].sudo().create({
+                'name': 'Overtime Compensation Employee Allocation',
+                'company_id': self.company.id,
+                'allocation_type': 'fixed_allocation',
+                'overtime_deductible': False,
+            })
+
+            # User can request another allocation even without overtime
+            allocation2 = self.env['hr.leave.allocation'].create({
+                'name': 'test allocation',
+                'holiday_status_id': leave_type.id,
+                'employee_id': self.employee.id,
+                'number_of_days': 1,
+                'state': 'draft',
+            })
+            allocation2.action_confirm()
+
+    def test_allocation_check_overtime_write(self):
+        self.new_attendance(check_in=datetime(2021, 1, 2, 8), check_out=datetime(2021, 1, 2, 16))
+        self.new_attendance(check_in=datetime(2021, 1, 3, 8), check_out=datetime(2021, 1, 3, 16))
+        self.assertEqual(self.employee.total_overtime, 16, 'Should have 16 hours of overtime')
+
+        alloc = self.env['hr.leave.allocation'].create({
+            'name': 'test allocation',
+            'holiday_status_id': self.leave_type_employee_allocation.id,
+            'employee_id': self.employee.id,
+            'number_of_days': 1,
+            'state': 'draft',
+        })
+        self.assertEqual(self.employee.total_overtime, 8)
+
+        with self.assertRaises(ValidationError), self.cr.savepoint():
+            alloc.number_of_days = 3
+
+        alloc.number_of_days = 2
+        self.assertEqual(self.employee.total_overtime, 0)
diff --git a/addons/hr_holidays_attendance/views/hr_employee_views.xml b/addons/hr_holidays_attendance/views/hr_employee_views.xml
index 53cc6d53e90..8d7af3d44d5 100644
--- a/addons/hr_holidays_attendance/views/hr_employee_views.xml
+++ b/addons/hr_holidays_attendance/views/hr_employee_views.xml
@@ -31,6 +31,23 @@
         </field>
     </record>
 
+    <record id="hr_employee_view_form_inherit" model="ir.ui.view">
+        <field name="name">hr.holidays.attendance.employee.view.form.inherit</field>
+        <field name="model">hr.employee</field>
+        <field name="inherit_id" ref="hr.view_employee_form"/>
+        <field name="arch" type="xml">
+            <xpath expr="//header" position="inside">
+                <button
+                    name="%(hr_leave_allocation_overtime_manager_action)d"
+                    string="Deduct Extra Hours"
+                    type="action"
+                    groups="hr_holidays.group_hr_holidays_user"
+                    context="{'default_employee_id': id, 'deduct_extra_hours': True}"
+                    attrs="{'invisible': [('total_overtime', '&lt;=', 1)]}"/>
+            </xpath>
+        </field>
+    </record>
+
     <record id="hr_employee_view_form" model="ir.ui.view">
         <field name="name">hr.employee.holidays.attendance.inherit</field>
         <field name="model">hr.employee</field>
diff --git a/addons/hr_holidays_attendance/views/hr_leave_allocation_views.xml b/addons/hr_holidays_attendance/views/hr_leave_allocation_views.xml
new file mode 100644
index 00000000000..18456a9ed99
--- /dev/null
+++ b/addons/hr_holidays_attendance/views/hr_leave_allocation_views.xml
@@ -0,0 +1,73 @@
+<?xml version='1.0' encoding='UTF-8' ?>
+<odoo>
+    <record id="hr_attendance_holidays_hr_leave_allocation_view_form_inherit" model="ir.ui.view">
+        <field name="model">hr.leave.allocation</field>
+        <field name="inherit_id" ref="hr_holidays.hr_leave_allocation_view_form" />
+        <field name="arch" type="xml">
+            <xpath expr="(//div[@name='duration_display']/span)[last()]" position="after">
+                <field name="hr_attendance_overtime" invisible="1" />
+                <field name="overtime_deductible" invisible="1" />
+                <field name="employee_overtime" invisible="1" />
+                <div class="oe_inline"
+                    attrs="{'invisible': ['|', '|', '|',
+                    ('hr_attendance_overtime', '=', False), ('employee_id', '=', False),
+                    ('overtime_deductible', '=', False), ('employee_overtime', '&lt;=', 0)]}">
+                    <field name="employee_overtime" nolabel="1" widget="float_time" class="text-success" /> Extra Hours Available
+                </div>
+            </xpath>
+        </field>
+    </record>
+
+    <record id="hr_leave_allocation_overtime_view_form" model="ir.ui.view">
+        <field name="model">hr.leave.allocation</field>
+        <field name="inherit_id" ref="hr_attendance_holidays_hr_leave_allocation_view_form_inherit" />
+        <field name="mode">primary</field>
+        <field name="priority">60</field>
+        <field name="arch" type="xml">
+            <xpath expr="//header" position="attributes">
+                <attribute name="invisible">1</attribute>
+            </xpath>
+            <div name="button_box" position="attributes">
+                <attribute name="invisible">1</attribute>
+            </div>
+            <xpath expr="//field[@name='holiday_status_id']" position="attributes">
+                <attribute name="domain">[('valid', '=', True), ('overtime_deductible', '=', True), ('allocation_type', '=', 'fixed_allocation')]</attribute>
+                <attribute name="options">{'no_create': True, 'no_open': True}</attribute>
+            </xpath>
+            <xpath expr="//sheet" position="after">
+                <footer>
+                    <button string="Save" special="save" class="btn btn-primary" close="1" />
+                    <button string="Discard" special="cancel" class="btn-secondary" close="1" />
+                </footer>
+            </xpath>
+        </field>
+    </record>
+
+    <record id="hr_leave_allocation_overtime_manager_view_form" model="ir.ui.view">
+        <field name="model">hr.leave.allocation</field>
+        <field name="inherit_id" ref="hr_leave_allocation_overtime_view_form" />
+        <field name="mode">primary</field>
+        <field name="priority">70</field>
+        <field name="arch" type="xml">
+            <xpath expr="//field[@name='holiday_status_id']" position="attributes">
+                <attribute name="domain">[('valid', '=', True), ('overtime_deductible', '=', True), ('allocation_type', '!=', 'no')]</attribute>
+            </xpath>
+        </field>
+    </record>
+
+    <record id="hr_leave_allocation_overtime_action" model="ir.actions.act_window">
+        <field name="name">New Allocation Request</field>
+        <field name="res_model">hr.leave.allocation</field>
+        <field name="view_mode">form</field>
+        <field name="view_ids" eval="[(5, 0, 0), (0, 0, {'view_mode': 'form', 'view_id': ref('hr_leave_allocation_overtime_view_form')})]"/>
+        <field name="target">new</field>
+    </record>
+
+    <record id="hr_leave_allocation_overtime_manager_action" model="ir.actions.act_window">
+        <field name="name">New Allocation Request</field>
+        <field name="res_model">hr.leave.allocation</field>
+        <field name="view_mode">form</field>
+        <field name="view_ids" eval="[(5, 0, 0), (0, 0, {'view_mode': 'form', 'view_id': ref('hr_leave_allocation_overtime_manager_view_form')})]"/>
+        <field name="target">new</field>
+    </record>
+</odoo>
diff --git a/addons/hr_holidays_attendance/views/hr_leave_type_views.xml b/addons/hr_holidays_attendance/views/hr_leave_type_views.xml
new file mode 100644
index 00000000000..99f5b635c36
--- /dev/null
+++ b/addons/hr_holidays_attendance/views/hr_leave_type_views.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<odoo>
+    <record id="hr_leave_type_view_form" model="ir.ui.view">
+        <field name="name">hr.leave.type.view.form.inherit</field>
+        <field name="model">hr.leave.type</field>
+        <field name="inherit_id" ref="hr_holidays.edit_holiday_status_form"/>
+        <field name="arch" type="xml">
+            <xpath expr="//field[@name='leave_validation_type']" position="after">
+                <field name="hr_attendance_overtime" invisible="1" />
+                <field name="overtime_deductible" attrs="{'invisible': [('hr_attendance_overtime', '=', False)]}"/>
+            </xpath>
+        </field>
+    </record>
+</odoo>
diff --git a/addons/hr_holidays_attendance/views/hr_leave_views.xml b/addons/hr_holidays_attendance/views/hr_leave_views.xml
new file mode 100644
index 00000000000..e02b5c88c30
--- /dev/null
+++ b/addons/hr_holidays_attendance/views/hr_leave_views.xml
@@ -0,0 +1,16 @@
+<?xml version='1.0' encoding='UTF-8' ?>
+<odoo>
+    <record id="hr_leave_view_form" model="ir.ui.view">
+        <field name="model">hr.leave</field>
+        <field name="inherit_id" ref="hr_holidays.hr_leave_view_form" />
+        <field name="arch" type="xml">
+            <xpath expr="(//div[@name='duration_display']/div)[last()]" position="after">
+                <field name="overtime_deductible" invisible="1" />
+                <field name="employee_overtime" invisible="1" />
+                <div attrs="{'invisible': ['|', '|', ('employee_id', '=', False), ('overtime_deductible', '=', False), ('employee_overtime', '&lt;=', 0)]}">
+                    <field name="employee_overtime" nolabel="1" widget="float_time" class="text-success" /> Extra Hours Available
+                </div>
+            </xpath>
+        </field>
+    </record>
+</odoo>
diff --git a/addons/hr_holidays_attendance/views/res_users_views.xml b/addons/hr_holidays_attendance/views/res_users_views.xml
new file mode 100644
index 00000000000..8b6d149baf9
--- /dev/null
+++ b/addons/hr_holidays_attendance/views/res_users_views.xml
@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<odoo>
+    <record id="res_users_view_form" model="ir.ui.view">
+        <field name="model">res.users</field>
+        <field name="inherit_id" ref="hr.res_users_view_form_profile"/>
+        <field name="arch" type="xml">
+            <xpath expr="//header" position="inside">
+                <field name="employee_id" invisible="1" />
+                <field name="request_overtime" invisible="1" />
+                <button
+                    name="%(hr_leave_allocation_overtime_action)d"
+                    string="Deduct Extra Hours"
+                    type="action"
+                    context="{'default_employee_id': employee_id, 'deduct_extra_hours': True}"
+                    attrs="{'invisible': [('request_overtime', '=', False)]}"/>
+            </xpath>
+        </field>
+    </record>
+</odoo>
diff --git a/addons/hr_work_entry_holidays/tests/test_performance.py b/addons/hr_work_entry_holidays/tests/test_performance.py
index 615b0faf33c..f83e76487eb 100644
--- a/addons/hr_work_entry_holidays/tests/test_performance.py
+++ b/addons/hr_work_entry_holidays/tests/test_performance.py
@@ -47,7 +47,7 @@ class TestWorkEntryHolidaysPerformance(TestWorkEntryHolidaysBase):
     @users('__system__', 'admin')
     @warmup
     def test_performance_leave_create(self):
-        with self.assertQueryCount(__system__=22, admin=23):
+        with self.assertQueryCount(__system__=24, admin=25):
             leave = self.create_leave(datetime(2018, 1, 1, 7, 0), datetime(2018, 1, 1, 18, 0))
         leave.action_refuse()
 
@@ -56,7 +56,7 @@ class TestWorkEntryHolidaysPerformance(TestWorkEntryHolidaysBase):
     def test_performance_leave_confirm(self):
         leave = self.create_leave(datetime(2018, 1, 1, 7, 0), datetime(2018, 1, 1, 18, 0))
         leave.action_draft()
-        with self.assertQueryCount(__system__=20, admin=21):
+        with self.assertQueryCount(__system__=22, admin=23):
             leave.action_confirm()
         leave.state = 'cancel'