diff --git a/addons/project/data/project_demo.xml b/addons/project/data/project_demo.xml
index c8b388a39b7..f8b0a6ddb0a 100644
--- a/addons/project/data/project_demo.xml
+++ b/addons/project/data/project_demo.xml
@@ -11,6 +11,10 @@
         <record id="base.group_user" model="res.groups">
             <field name="implied_ids" eval="[Command.link(ref('group_project_milestone'))]"/>
         </record>
+        <!-- The feature is also enabled to portal user because the feature is displayed in the Project Sharing feature -->
+        <record id="base.group_portal" model="res.groups">
+            <field name="implied_ids" eval="[Command.link(ref('group_project_milestone'))]"/>
+        </record>
 
         <!-- Categories -->
         <record id="project_tags_00" model="project.tags">
diff --git a/addons/project/models/project.py b/addons/project/models/project.py
index 82c5ec9b59b..1410b39ae0a 100644
--- a/addons/project/models/project.py
+++ b/addons/project/models/project.py
@@ -45,6 +45,9 @@ PROJECT_TASK_READABLE_FIELDS = {
     'legend_done',
     'user_ids',
     'display_parent_task_button',
+    'allow_milestones',
+    'milestone_id',
+    'has_late_and_unreached_milestone',
 }
 
 PROJECT_TASK_WRITABLE_FIELDS = {
@@ -1138,7 +1141,6 @@ class Task(models.Model):
     has_late_and_unreached_milestone = fields.Boolean(
         compute='_compute_has_late_and_unreached_milestone',
         search='_search_has_late_and_unreached_milestone',
-        groups='project.group_project_milestone',
     )
 
     # Task Dependencies fields
@@ -2024,7 +2026,7 @@ class Task(models.Model):
         if all(not task.allow_milestones for task in self):
             self.has_late_and_unreached_milestone = False
             return
-        late_milestones = self.env['project.milestone']._search([
+        late_milestones = self.env['project.milestone'].sudo()._search([  # sudo is needed for the portal user in Project Sharing.
             ('id', 'in', self.milestone_id.ids),
             ('is_reached', '=', False),
             ('deadline', '<', fields.Date.today()),
diff --git a/addons/project/models/res_config_settings.py b/addons/project/models/res_config_settings.py
index 0dd42cc8a62..93ebc05699a 100644
--- a/addons/project/models/res_config_settings.py
+++ b/addons/project/models/res_config_settings.py
@@ -14,7 +14,7 @@ class ResConfigSettings(models.TransientModel):
     group_project_stages = fields.Boolean("Project Stages", implied_group="project.group_project_stages")
     group_project_recurring_tasks = fields.Boolean("Recurring Tasks", implied_group="project.group_project_recurring_tasks")
     group_project_task_dependencies = fields.Boolean("Task Dependencies", implied_group="project.group_project_task_dependencies")
-    group_project_milestone = fields.Boolean('Milestones', implied_group='project.group_project_milestone')
+    group_project_milestone = fields.Boolean('Milestones', implied_group='project.group_project_milestone', group='base.group_portal,base.group_user')
     rating_status = fields.Selection(
         [('stage', 'Rating when changing stage'),
          ('periodic', 'Periodic rating')
diff --git a/addons/project/views/project_sharing_views.xml b/addons/project/views/project_sharing_views.xml
index a148174051b..f5d06ca7d48 100644
--- a/addons/project/views/project_sharing_views.xml
+++ b/addons/project/views/project_sharing_views.xml
@@ -44,6 +44,8 @@
                 <field name="legend_blocked" invisible="1"/>
                 <field name="legend_normal" invisible="1"/>
                 <field name="legend_done" invisible="1"/>
+                <field name="allow_milestones" />
+                <field name="has_late_and_unreached_milestone"/>
                 <progressbar field="kanban_state" colors='{"done": "success", "blocked": "danger", "normal": "muted"}'/>
                 <templates>
                 <t t-name="kanban-box">
@@ -56,6 +58,10 @@
                                         <t t-else=""><field name="name" widget="name_with_subtask_count"/></t>
                                     </strong>
                                     <span invisible="context.get('default_project_id', False)"><br/><field name="project_id" required="1"/></span>
+                                    <span t-if="record.allow_milestones.raw_value and record.milestone_id.raw_value" t-attf-class="{{record.has_late_and_unreached_milestone.raw_value ? 'text-danger' : ''}}">
+                                        <br/>
+                                        <field name="milestone_id" />
+                                    </span>
                                     <br />
                                     <t t-if="record.partner_id.value">
                                         <span t-if="!record.partner_is_company.raw_value">
@@ -119,10 +125,12 @@
                 <field name="is_closed" invisible="1" />
                 <field name="allow_subtasks" invisible="1" />
                 <field name="sequence" invisible="1" readonly="1"/>
+                <field name="allow_milestones" invisible="1"/>
                 <field name="priority" widget="priority" optional="show" nolabel="1"/>
                 <field name="name" widget="name_with_subtask_count"/>
                 <field name="child_text" invisible="1"/>
                 <field name="company_id" invisible="1"/>
+                <field name="milestone_id" attrs="{'column_invisible': [('allow_milestones', '=', False)]}"/>
                 <field name="partner_id" optional="hide"/>
                 <field name="portal_user_names" string="Assignees" optional="show"/>
                 <field name="date_deadline" optional="hide" widget="remaining_days" attrs="{'invisible': [('is_closed', '=', True)]}"/>
@@ -179,6 +187,13 @@
                         <group>
                             <field name="project_id" invisible="1"/>
                             <field name="display_project_id" string="Project" invisible="1"/>
+                            <field name="allow_milestones" invisible="1"/>
+                            <field name="milestone_id"
+                                placeholder="e.g. Product Launch"
+                                context="{'default_project_id': project_id if not parent_id or not display_project_id else display_project_id}"
+                                attrs="{'invisible': [('allow_milestones', '=', False)]}"
+                                options="{'no_open': True, 'no_create': True, 'no_edit': True}"
+                            />
                             <field name="user_ids" invisible="1" />
                             <field name="portal_user_names"
                                 string="Assignees"
@@ -207,6 +222,12 @@
                                     <field name="sequence" widget="handle"/>
                                     <field name="name"/>
                                     <field name="display_project_id" string="Project" optional="hide" invisible="1"/>
+                                    <field name="allow_milestones" invisible="1"/>
+                                    <field name="milestone_id"
+                                        optional="hide"
+                                        context="{'default_project_id': display_project_id or project_id}"
+                                        attrs="{'invisible': [('allow_milestones', '=', False)], 'column_invisible': [('parent.allow_milestones', '=', False)]}"
+                                    />
                                     <field name="company_id" invisible="1"/>
                                     <field name="partner_id" options="{'no_open': True, 'no_create': True, 'no_edit': True}" optional="hide"/>
                                     <field name="user_ids" invisible="1" />
@@ -240,6 +261,7 @@
                 <field name="partner_id" operator="child_of"/>
                 <field name="stage_id"/>
                 <field string="Project" name="display_project_id"/>
+                <field name="milestone_id" groups="project.group_project_milestone"/>
                 <filter string="Unassigned" name="unassigned" domain="[('user_ids', '=', False)]"/>
                 <separator/>
                 <filter string="High Priority" name="high_priority" domain="[('priority', '=', 1)]"/>
@@ -253,6 +275,7 @@
                     domain="[('activity_ids.date_deadline', '&gt;', context_today().strftime('%Y-%m-%d'))]"/>
                 <group expand="0" string="Group By">
                     <filter string="Stage" name="stage" context="{'group_by': 'stage_id'}"/>
+                    <filter string="Milestone" name="milestone" context="{'group_by': 'milestone_id'}" groups="project.group_project_milestone"/>
                     <filter string="Customer" name="customer" context="{'group_by': 'partner_id'}"/>
                     <filter string="Kanban State" name="kanban_state" context="{'group_by': 'kanban_state'}"/>
                     <filter string="Deadline" name="date_deadline" context="{'group_by': 'date_deadline'}"/>