diff --git a/pytest_django/fixtures.py b/pytest_django/fixtures.py
index b14c737a..62310edc 100644
--- a/pytest_django/fixtures.py
+++ b/pytest_django/fixtures.py
@@ -44,6 +44,7 @@
     "db",
     "transactional_db",
     "django_db_reset_sequences",
+    "django_db_all_databases",
     "django_db_serialized_rollback",
     "admin_user",
     "django_user_model",
@@ -190,6 +191,7 @@ def _django_db_helper(
         or ("transactional_db" in request.fixturenames or "live_server" in request.fixturenames)
     )
     reset_sequences = reset_sequences or ("django_db_reset_sequences" in request.fixturenames)
+    databases = databases or ("__all__" if "django_db_all_databases" in request.fixturenames else None)
     serialized_rollback = serialized_rollback or (
         "django_db_serialized_rollback" in request.fixturenames
     )
@@ -397,6 +399,10 @@ def django_db_serialized_rollback(
     # is requested.
 
 
+def django_db_all_databases(_django_db_helper: None):
+    """TODO: write a docstring"""
+
+
 @pytest.fixture()
 def client() -> django.test.Client:
     """A Django test client instance."""