diff --git a/partner_email_sync_portal_login/README.md b/partner_email_sync_portal_login/README.md
new file mode 100644
index 0000000..7214f18
--- /dev/null
+++ b/partner_email_sync_portal_login/README.md
@@ -0,0 +1,24 @@
+# Partner Email Sync Portal Login
+
+When the email of a contact that has a **portal user** is changed and saved:
+
+- the user login is updated with the new (normalized) email, and
+- a password reset email is sent to the new address.
+
+A note is posted in the contact chatter with the result.
+
+## Behaviour details
+
+- Only portal users are affected; internal users are never modified.
+- Empty or invalid emails are ignored (login is kept).
+- Changes that only differ in letter case do not trigger anything.
+- If another user already uses the new email as login, the change is
+  blocked with an error message.
+- If the reset email cannot be sent, the login is still updated and the
+  error is recorded in the chatter.
+- From the portal access wizard ("Grant portal access" / "Invite again")
+  the login is synced but no reset email is sent, since the wizard sends
+  its own invitation.
+- Use the context key `skip_portal_login_sync` to disable the behaviour
+  (e.g. in imports).
+- Changing the login closes the user's open sessions.
diff --git a/partner_email_sync_portal_login/__init__.py b/partner_email_sync_portal_login/__init__.py
new file mode 100644
index 0000000..9b42961
--- /dev/null
+++ b/partner_email_sync_portal_login/__init__.py
@@ -0,0 +1,2 @@
+from . import models
+from . import wizard
diff --git a/partner_email_sync_portal_login/__manifest__.py b/partner_email_sync_portal_login/__manifest__.py
new file mode 100644
index 0000000..b5ea4c6
--- /dev/null
+++ b/partner_email_sync_portal_login/__manifest__.py
@@ -0,0 +1,17 @@
+# Copyright 2026 Criptomart
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+{
+    "name": "Partner Email Sync Portal Login",
+    "summary": "Update the portal user login and send a password reset "
+    "email when the partner email changes",
+    "version": "16.0.1.0.0",
+    "category": "Tools",
+    "website": "https://criptomart.net",
+    "author": "Criptomart",
+    "maintainers": ["criptomart"],
+    "license": "AGPL-3",
+    "depends": ["portal"],
+    "data": [],
+    "installable": True,
+}
diff --git a/partner_email_sync_portal_login/i18n/es.po b/partner_email_sync_portal_login/i18n/es.po
new file mode 100644
index 0000000..d7269cf
--- /dev/null
+++ b/partner_email_sync_portal_login/i18n/es.po
@@ -0,0 +1,67 @@
+# Translation of Odoo Server.
+# This file contains the translation of the following modules:
+# 	* partner_email_sync_portal_login
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Odoo Server 16.0\n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2026-10-06 09:57+0000\n"
+"PO-Revision-Date: 2026-10-06 09:57+0000\n"
+"Last-Translator: \n"
+"Language-Team: \n"
+"Language: es\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: \n"
+"Plural-Forms: \n"
+
+#. module: partner_email_sync_portal_login
+#. odoo-python
+#: code:addons/partner_email_sync_portal_login/models/res_partner.py:0
+#, python-format
+msgid ""
+"Cannot change the email of %(partner)s: there is already a user with login "
+"%(login)s."
+msgstr ""
+"No se puede cambiar el email de %(partner)s: ya existe un usuario con el login "
+"%(login)s."
+
+#. module: partner_email_sync_portal_login
+#: model:ir.model,name:partner_email_sync_portal_login.model_res_partner
+msgid "Contact"
+msgstr "Contacto"
+
+#. module: partner_email_sync_portal_login
+#: model:ir.model,name:partner_email_sync_portal_login.model_portal_wizard_user
+msgid "Portal User Config"
+msgstr "Configuración de usuario de portal"
+
+#. module: partner_email_sync_portal_login
+#. odoo-python
+#: code:addons/partner_email_sync_portal_login/models/res_partner.py:0
+#, python-format
+msgid ""
+"Portal user login changed from %(old)s to %(new)s and a password reset email"
+" has been sent."
+msgstr ""
+"Login del usuario de portal cambiado de %(old)s a %(new)s y enviado el correo "
+"de restablecimiento de contraseña."
+
+#. module: partner_email_sync_portal_login
+#. odoo-python
+#: code:addons/partner_email_sync_portal_login/models/res_partner.py:0
+#, python-format
+msgid ""
+"Portal user login changed from %(old)s to %(new)s, but the password reset "
+"email could not be sent: %(error)s"
+msgstr ""
+"Login del usuario de portal cambiado de %(old)s a %(new)s, pero no se ha podido "
+"enviar el correo de restablecimiento de contraseña: %(error)s"
+
+#. module: partner_email_sync_portal_login
+#. odoo-python
+#: code:addons/partner_email_sync_portal_login/models/res_partner.py:0
+#, python-format
+msgid "Portal user login changed from %(old)s to %(new)s."
+msgstr "Login del usuario de portal cambiado de %(old)s a %(new)s."
diff --git a/partner_email_sync_portal_login/i18n/partner_email_sync_portal_login.pot b/partner_email_sync_portal_login/i18n/partner_email_sync_portal_login.pot
new file mode 100644
index 0000000..90e3269
--- /dev/null
+++ b/partner_email_sync_portal_login/i18n/partner_email_sync_portal_login.pot
@@ -0,0 +1,60 @@
+# Translation of Odoo Server.
+# This file contains the translation of the following modules:
+# 	* partner_email_sync_portal_login
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Odoo Server 16.0\n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2026-10-06 09:57+0000\n"
+"PO-Revision-Date: 2026-10-06 09:57+0000\n"
+"Last-Translator: \n"
+"Language-Team: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: \n"
+"Plural-Forms: \n"
+
+#. module: partner_email_sync_portal_login
+#. odoo-python
+#: code:addons/partner_email_sync_portal_login/models/res_partner.py:0
+#, python-format
+msgid ""
+"Cannot change the email of %(partner)s: there is already a user with login "
+"%(login)s."
+msgstr ""
+
+#. module: partner_email_sync_portal_login
+#: model:ir.model,name:partner_email_sync_portal_login.model_res_partner
+msgid "Contact"
+msgstr ""
+
+#. module: partner_email_sync_portal_login
+#: model:ir.model,name:partner_email_sync_portal_login.model_portal_wizard_user
+msgid "Portal User Config"
+msgstr ""
+
+#. module: partner_email_sync_portal_login
+#. odoo-python
+#: code:addons/partner_email_sync_portal_login/models/res_partner.py:0
+#, python-format
+msgid ""
+"Portal user login changed from %(old)s to %(new)s and a password reset email"
+" has been sent."
+msgstr ""
+
+#. module: partner_email_sync_portal_login
+#. odoo-python
+#: code:addons/partner_email_sync_portal_login/models/res_partner.py:0
+#, python-format
+msgid ""
+"Portal user login changed from %(old)s to %(new)s, but the password reset "
+"email could not be sent: %(error)s"
+msgstr ""
+
+#. module: partner_email_sync_portal_login
+#. odoo-python
+#: code:addons/partner_email_sync_portal_login/models/res_partner.py:0
+#, python-format
+msgid "Portal user login changed from %(old)s to %(new)s."
+msgstr ""
diff --git a/partner_email_sync_portal_login/models/__init__.py b/partner_email_sync_portal_login/models/__init__.py
new file mode 100644
index 0000000..91fed54
--- /dev/null
+++ b/partner_email_sync_portal_login/models/__init__.py
@@ -0,0 +1 @@
+from . import res_partner
diff --git a/partner_email_sync_portal_login/models/res_partner.py b/partner_email_sync_portal_login/models/res_partner.py
new file mode 100644
index 0000000..e22276e
--- /dev/null
+++ b/partner_email_sync_portal_login/models/res_partner.py
@@ -0,0 +1,102 @@
+# Copyright 2026 Criptomart
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+import logging
+
+from markupsafe import Markup
+
+from odoo import _, models
+from odoo.exceptions import UserError
+from odoo.tools import email_normalize
+
+_logger = logging.getLogger(__name__)
+
+
+class ResPartner(models.Model):
+    _inherit = "res.partner"
+
+    def write(self, vals):
+        res = super().write(vals)
+        if "email" in vals and not self.env.context.get("skip_portal_login_sync"):
+            self._sync_portal_user_login()
+        return res
+
+    def _get_portal_users_to_sync(self):
+        self.ensure_one()
+        group_portal = self.env.ref("base.group_portal")
+        return self.sudo().user_ids.filtered(lambda u: group_portal in u.groups_id)
+
+    def _sync_portal_user_login(self):
+        """Set the partner email as login of its portal users and send them
+        a password reset email."""
+        Users = self.env["res.users"].sudo().with_context(active_test=False)
+        for partner in self:
+            users = partner._get_portal_users_to_sync()
+            if not users:
+                continue
+            new_login = email_normalize(partner.email)
+            if not new_login:
+                _logger.info(
+                    "Portal login not synced for partner %s: invalid email %r",
+                    partner.id,
+                    partner.email,
+                )
+                continue
+            for user in users:
+                if email_normalize(user.login) == new_login:
+                    continue
+                if Users.search_count(
+                    [("login", "=", new_login), ("id", "!=", user.id)]
+                ):
+                    raise UserError(
+                        _(
+                            "Cannot change the email of %(partner)s: there is "
+                            "already a user with login %(login)s.",
+                            partner=partner.display_name,
+                            login=new_login,
+                        )
+                    )
+                old_login = user.login
+                user.write({"login": new_login})
+                _logger.info(
+                    "Portal user %s login changed from %s to %s",
+                    user.id,
+                    old_login,
+                    new_login,
+                )
+                if self.env.context.get("portal_login_sync_no_mail"):
+                    body = _(
+                        "Portal user login changed from %(old)s to %(new)s.",
+                        old=old_login,
+                        new=new_login,
+                    )
+                else:
+                    body = partner._send_portal_login_reset_password(
+                        user, old_login, new_login
+                    )
+                partner.sudo().message_post(body=Markup("<p>%s</p>") % body)
+
+    def _send_portal_login_reset_password(self, user, old_login, new_login):
+        try:
+            with self.env.cr.savepoint():
+                user.action_reset_password()
+        except Exception as e:
+            # Do not block the email change if the reset email cannot be sent
+            _logger.warning(
+                "Password reset email for portal user %s could not be sent: %s",
+                user.id,
+                e,
+            )
+            return _(
+                "Portal user login changed from %(old)s to %(new)s, but the "
+                "password reset email could not be sent: %(error)s",
+                old=old_login,
+                new=new_login,
+                error=str(e),
+            )
+        return _(
+            "Portal user login changed from %(old)s to %(new)s and a password "
+            "reset email has been sent.",
+            old=old_login,
+            new=new_login,
+        )
diff --git a/partner_email_sync_portal_login/tests/__init__.py b/partner_email_sync_portal_login/tests/__init__.py
new file mode 100644
index 0000000..71522fb
--- /dev/null
+++ b/partner_email_sync_portal_login/tests/__init__.py
@@ -0,0 +1 @@
+from . import test_partner_email_sync_portal_login
diff --git a/partner_email_sync_portal_login/tests/test_partner_email_sync_portal_login.py b/partner_email_sync_portal_login/tests/test_partner_email_sync_portal_login.py
new file mode 100644
index 0000000..de52ecc
--- /dev/null
+++ b/partner_email_sync_portal_login/tests/test_partner_email_sync_portal_login.py
@@ -0,0 +1,99 @@
+# Copyright 2026 Criptomart
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from unittest.mock import patch
+
+from odoo.exceptions import UserError
+from odoo.tests import TransactionCase, tagged
+
+from odoo.addons.auth_signup.models.res_users import ResUsers
+
+RESET_PASSWORD = "action_reset_password"
+
+
+@tagged("post_install", "-at_install")
+class TestPartnerEmailSyncPortalLogin(TransactionCase):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.env = cls.env(context=dict(cls.env.context, tracking_disable=True))
+        Users = cls.env["res.users"].with_context(no_reset_password=True)
+        cls.portal_user = Users.create(
+            {
+                "name": "Portal Member",
+                "login": "member@example.com",
+                "email": "member@example.com",
+                "groups_id": [(6, 0, [cls.env.ref("base.group_portal").id])],
+            }
+        )
+        cls.internal_user = Users.create(
+            {
+                "name": "Internal Member",
+                "login": "internal@example.com",
+                "email": "internal@example.com",
+                "groups_id": [(6, 0, [cls.env.ref("base.group_user").id])],
+            }
+        )
+
+    def test_portal_user_login_synced_and_reset_sent(self):
+        with patch.object(ResUsers, RESET_PASSWORD, autospec=True) as reset:
+            self.portal_user.partner_id.email = "New.Member@Example.com"
+        self.assertEqual(self.portal_user.login, "new.member@example.com")
+        reset.assert_called_once()
+        self.assertEqual(reset.call_args.args[0], self.portal_user)
+
+    def test_internal_user_not_synced(self):
+        with patch.object(ResUsers, RESET_PASSWORD, autospec=True) as reset:
+            self.internal_user.partner_id.email = "other@example.com"
+        self.assertEqual(self.internal_user.login, "internal@example.com")
+        reset.assert_not_called()
+
+    def test_partner_without_user(self):
+        partner = self.env["res.partner"].create(
+            {"name": "No User", "email": "nouser@example.com"}
+        )
+        with patch.object(ResUsers, RESET_PASSWORD, autospec=True) as reset:
+            partner.email = "nouser2@example.com"
+        reset.assert_not_called()
+
+    def test_invalid_or_empty_email_keeps_login(self):
+        with patch.object(ResUsers, RESET_PASSWORD, autospec=True) as reset:
+            self.portal_user.partner_id.email = False
+            self.portal_user.partner_id.email = "not-an-email"
+        self.assertEqual(self.portal_user.login, "member@example.com")
+        reset.assert_not_called()
+
+    def test_same_email_different_case_not_resent(self):
+        with patch.object(ResUsers, RESET_PASSWORD, autospec=True) as reset:
+            self.portal_user.partner_id.email = "MEMBER@example.com"
+        self.assertEqual(self.portal_user.login, "member@example.com")
+        reset.assert_not_called()
+
+    def test_login_already_used(self):
+        with self.assertRaises(UserError):
+            self.portal_user.partner_id.email = "internal@example.com"
+
+    def test_reset_email_failure_does_not_block(self):
+        with patch.object(
+            ResUsers, RESET_PASSWORD, autospec=True, side_effect=UserError("boom")
+        ):
+            self.portal_user.partner_id.email = "fail@example.com"
+        self.assertEqual(self.portal_user.login, "fail@example.com")
+
+    def test_skip_context(self):
+        partner = self.portal_user.partner_id.with_context(
+            skip_portal_login_sync=True
+        )
+        with patch.object(ResUsers, RESET_PASSWORD, autospec=True) as reset:
+            partner.email = "skip@example.com"
+        self.assertEqual(self.portal_user.login, "member@example.com")
+        reset.assert_not_called()
+
+    def test_no_mail_context_syncs_login_only(self):
+        partner = self.portal_user.partner_id.with_context(
+            portal_login_sync_no_mail=True
+        )
+        with patch.object(ResUsers, RESET_PASSWORD, autospec=True) as reset:
+            partner.email = "wizard@example.com"
+        self.assertEqual(self.portal_user.login, "wizard@example.com")
+        reset.assert_not_called()
diff --git a/partner_email_sync_portal_login/wizard/__init__.py b/partner_email_sync_portal_login/wizard/__init__.py
new file mode 100644
index 0000000..8bff21f
--- /dev/null
+++ b/partner_email_sync_portal_login/wizard/__init__.py
@@ -0,0 +1 @@
+from . import portal_wizard
diff --git a/partner_email_sync_portal_login/wizard/portal_wizard.py b/partner_email_sync_portal_login/wizard/portal_wizard.py
new file mode 100644
index 0000000..d212959
--- /dev/null
+++ b/partner_email_sync_portal_login/wizard/portal_wizard.py
@@ -0,0 +1,14 @@
+# Copyright 2026 Criptomart
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from odoo import models
+
+
+class PortalWizardUser(models.TransientModel):
+    _inherit = "portal.wizard.user"
+
+    def _update_partner_email(self):
+        # The portal wizard already sends its own invitation email
+        return super(
+            PortalWizardUser, self.with_context(portal_login_sync_no_mail=True)
+        )._update_partner_email()