diff --git a/api/permissions/permission_service.py b/api/permissions/permission_service.py
index 07b25b4124c4..ad1ab41cb86f 100644
--- a/api/permissions/permission_service.py
+++ b/api/permissions/permission_service.py
@@ -199,26 +199,47 @@ def get_permitted_environments_for_master_api_key(
 def user_has_organisation_permission(
     user: "FFAdminUser", organisation: Organisation, permission_key: str
 ) -> bool:
+    """
+    Check if user has the given permission on an organisation.
+
+    Runs separate queries with early returns:
+    1. Organisation admin - admins hold every organisation permission.
+    2. Organisation membership - check to prevent orphaned permission
+       records from granting access.
+    3. Direct user permission - checks UserOrganisationPermission.
+    4. Group permission - checks via user's group memberships.
+    5. Role permission - RBAC check, only if enabled.
+    """
     if is_user_organisation_admin(user, organisation):
         return True
 
+    # Check: verify user belongs to the organisation
+    if not Organisation.objects.filter(id=organisation.id, users=user).exists():
+        return False
+
     # NOTE: since we store organisation admin slightly differently
-    # compared to project and environment `get_base_permission_filter`
-    # with allow_admin=True will not work for organisation
-    base_filter = get_base_permission_filter(
-        user,
-        Organisation,  # type: ignore[arg-type]
-        permission_key,
-        allow_admin=False,
-    )
-    filter_ = base_filter & Q(id=organisation.id)
+    # compared to project and environment, allow_admin=True will not
+    # work for organisation
+
+    # Check direct permission
+    user_filter = get_user_permission_filter(user, permission_key, allow_admin=False)
+    if Organisation.objects.filter(user_filter & Q(id=organisation.id)).exists():
+        return True
 
-    queryset = Organisation.objects.filter(filter_)
+    # Check group permission
+    group_filter = get_group_permission_filter(user, permission_key, allow_admin=False)
+    if Organisation.objects.filter(group_filter & Q(id=organisation.id)).exists():
+        return True
 
-    # Final check to verify that user belongs to organisation
-    queryset = queryset.filter(users=user)
+    # Check role permission (only if RBAC installed)
+    if settings.IS_RBAC_INSTALLED:  # pragma: no cover
+        role_filter = get_role_permission_filter(
+            user, Organisation, permission_key, allow_admin=False
+        )
+        if Organisation.objects.filter(role_filter & Q(id=organisation.id)).exists():
+            return True
 
-    return queryset.exists()  # type: ignore[no-any-return]
+    return False
 
 
 def master_api_key_has_organisation_permission(
diff --git a/api/tests/unit/permissions/permission_service/test_user_has_organisation_permissions.py b/api/tests/unit/permissions/permission_service/test_user_has_organisation_permissions.py
index 1798892cc473..1706fbe64420 100644
--- a/api/tests/unit/permissions/permission_service/test_user_has_organisation_permissions.py
+++ b/api/tests/unit/permissions/permission_service/test_user_has_organisation_permissions.py
@@ -1,3 +1,5 @@
+import typing
+
 from organisations.models import Organisation, UserOrganisation
 from organisations.permissions.models import (
     OrganisationPermissionModel,
@@ -156,3 +158,97 @@ def test_user_has_organisation_permission__user_removed_from_organisation__retur
         organisation=organisation,
         permission_key=CREATE_PROJECT,
     )
+
+
+def test_user_has_organisation_permission__direct_permission__short_circuits_in_three_queries(
+    staff_user: FFAdminUser,
+    organisation: Organisation,
+    django_assert_num_queries: typing.Any,
+) -> None:
+    # Given
+    user_org_permission = UserOrganisationPermission.objects.create(
+        user=staff_user, organisation=organisation
+    )
+    user_org_permission.permissions.add(CREATE_PROJECT)  # type: ignore[arg-type]
+
+    # When
+    # Should take only 3 queries:
+    # 1. Check if user is org admin (is_user_organisation_admin)
+    # 2. Check organisation membership
+    # 3. Check direct user permission (short-circuits here)
+    with django_assert_num_queries(3):
+        result = user_has_organisation_permission(
+            staff_user, organisation, CREATE_PROJECT
+        )
+
+    # Then
+    assert result is True
+
+
+def test_user_has_organisation_permission__group_permission__short_circuits_in_four_queries(
+    staff_user: FFAdminUser,
+    organisation: Organisation,
+    user_permission_group: UserPermissionGroup,
+    django_assert_num_queries: typing.Any,
+) -> None:
+    # Given
+    user_permission_group.users.add(staff_user)
+    group_org_permission = UserPermissionGroupOrganisationPermission.objects.create(
+        group=user_permission_group, organisation=organisation
+    )
+    group_org_permission.permissions.add(CREATE_PROJECT)  # type: ignore[arg-type]
+
+    # When
+    # Should take only 4 queries:
+    # 1. Check if user is org admin (is_user_organisation_admin)
+    # 2. Check organisation membership
+    # 3. Check direct user permission (not found)
+    # 4. Check group permission (short-circuits here)
+    with django_assert_num_queries(4):
+        result = user_has_organisation_permission(
+            staff_user, organisation, CREATE_PROJECT
+        )
+
+    # Then
+    assert result is True
+
+
+def test_user_has_organisation_permission__no_permissions_assigned__checks_each_source_in_four_queries(
+    staff_user: FFAdminUser,
+    organisation: Organisation,
+    django_assert_num_queries: typing.Any,
+) -> None:
+    # Given / When
+    # Should take exactly 4 queries, one per permission source — never a
+    # single combined query joining the user and group permission tables:
+    # 1. Check if user is org admin (is_user_organisation_admin)
+    # 2. Check organisation membership
+    # 3. Check direct user permission (not found)
+    # 4. Check group permission (not found; role check skipped without RBAC)
+    with django_assert_num_queries(4):
+        result = user_has_organisation_permission(
+            staff_user, organisation, MANAGE_USER_GROUPS
+        )
+
+    # Then
+    assert result is False
+
+
+def test_user_has_organisation_permission__user_not_in_organisation__short_circuits_in_two_queries(
+    organisation: Organisation,
+    django_assert_num_queries: typing.Any,
+) -> None:
+    # Given
+    user = FFAdminUser.objects.create(email="not-a-member@example.com")
+
+    # When
+    # Should take only 2 queries:
+    # 1. Check if user is org admin (is_user_organisation_admin)
+    # 2. Check organisation membership (short-circuits here)
+    with django_assert_num_queries(2):
+        result = user_has_organisation_permission(
+            user, organisation, MANAGE_USER_GROUPS
+        )
+
+    # Then
+    assert result is False
diff --git a/api/tests/unit/users/test_unit_users_models.py b/api/tests/unit/users/test_unit_users_models.py
index 475a28af9647..e95e622d62dc 100644
--- a/api/tests/unit/users/test_unit_users_models.py
+++ b/api/tests/unit/users/test_unit_users_models.py
@@ -9,7 +9,10 @@
 from organisations.permissions.permissions import ORGANISATION_PERMISSIONS
 from projects.models import Project
 from tests.types import WithProjectPermissionsCallable
-from users.models import FFAdminUser, UserPermissionGroup
+from users.models import (
+    FFAdminUser,
+    UserPermissionGroup,
+)
 
 
 def test_belongs_to__user_in_organisation__returns_true(