diff --git a/addons/project/i18n/project.pot b/addons/project/i18n/project.pot
index 8b072f5ab0f..6cef246111d 100644
--- a/addons/project/i18n/project.pot
+++ b/addons/project/i18n/project.pot
@@ -576,6 +576,14 @@ msgstr ""
 msgid "A tag with the same name already exists."
 msgstr ""
 
+#. module: project
+#: code:addons/project/models/project.py:0
+#, python-format
+msgid ""
+"A personal stage cannot be linked to a project because it is only visible to"
+" its corresponding user."
+msgstr ""
+
 #. module: project
 #: model:ir.model.constraint,message:project.constraint_project_task_user_rel_project_personal_stage_unique
 msgid "A task can only have a single personal stage per user."
diff --git a/addons/project/models/project.py b/addons/project/models/project.py
index 25f40dcd2ab..9b12cbaac24 100644
--- a/addons/project/models/project.py
+++ b/addons/project/models/project.py
@@ -169,6 +169,11 @@ class ProjectTaskType(models.Model):
             else:
                 stage.disabled_rating_warning = False
 
+    @api.constrains('user_id', 'project_ids')
+    def _check_personal_stage_not_linked_to_projects(self):
+        if any(stage.user_id and stage.project_ids for stage in self):
+            raise UserError(_('A personal stage cannot be linked to a project because it is only visible to its corresponding user.'))
+
     def remove_personal_stage(self):
         """
         Remove a personal stage, tasks using that stage will move to the first
diff --git a/addons/project/tests/__init__.py b/addons/project/tests/__init__.py
index fb617a77540..c0c2e69792c 100644
--- a/addons/project/tests/__init__.py
+++ b/addons/project/tests/__init__.py
@@ -12,6 +12,7 @@ from . import test_project_sharing
 from . import test_project_sharing_portal_access
 from . import test_project_sharing_ui
 from . import test_project_subtasks
+from . import test_project_task_type
 from . import test_project_ui
 from . import test_project_update_access_rights
 from . import test_project_update_flow
diff --git a/addons/project/tests/test_project_task_type.py b/addons/project/tests/test_project_task_type.py
new file mode 100644
index 00000000000..98f0e965008
--- /dev/null
+++ b/addons/project/tests/test_project_task_type.py
@@ -0,0 +1,59 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo.exceptions import UserError
+from odoo.addons.project.tests.test_project_base import TestProjectCommon
+
+
+class TestProjectTaskType(TestProjectCommon):
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestProjectTaskType, cls).setUpClass()
+
+        cls.stage_created = cls.env['project.task.type'].create({
+            'name': 'Stage Already Created',
+        })
+
+    def test_create_stage(self):
+        '''
+        Verify that it is not possible to add to a newly created stage a `user_id` and a `project_ids`
+        '''
+        with self.assertRaises(UserError):
+            self.env['project.task.type'].create({
+                'name': 'New Stage',
+                'user_id': self.uid,
+                'project_ids': [self.project_goats.id],
+            })
+
+    def test_modify_existing_stage(self):
+        '''
+        - case 1: [`user_id`: not set, `project_ids`: not set] | Add `user_id` and `project_ids` => UserError
+        - case 2: [`user_id`: set, `project_ids`: not set]  | Add `project_ids` => UserError
+        - case 3: [`user_id`: not set, `project_ids`: set] | Add `user_id` => UserError
+        '''
+        # case 1
+        with self.assertRaises(UserError):
+            self.stage_created.write({
+                'user_id': self.uid,
+                'project_ids': [self.project_goats.id],
+            })
+
+        # case 2
+        self.stage_created.write({
+            'user_id': self.uid,
+        })
+        with self.assertRaises(UserError):
+            self.stage_created.write({
+                'project_ids': [self.project_goats.id],
+            })
+
+        # case 3
+        self.stage_created.write({
+            'user_id': False,
+            'project_ids': [self.project_goats.id],
+        })
+        with self.assertRaises(UserError):
+            self.stage_created.write({
+                'user_id': self.uid,
+            })