diff --git a/changelog.d/17628.doc b/changelog.d/17628.doc
new file mode 100644
index 00000000000..8b9f436e5f5
--- /dev/null
+++ b/changelog.d/17628.doc
@@ -0,0 +1 @@
+Clarify the docstring of `test_forget_when_not_left`.
\ No newline at end of file
diff --git a/tests/handlers/test_room_member.py b/tests/handlers/test_room_member.py
index 213a66ed1a1..681e6379c39 100644
--- a/tests/handlers/test_room_member.py
+++ b/tests/handlers/test_room_member.py
@@ -380,7 +380,7 @@ def test_leave_and_forget_last_user(self) -> None:
         )
 
     def test_forget_when_not_left(self) -> None:
-        """Tests that a user cannot not forgets a room that has not left."""
+        """Tests that a user cannot forget a room that they are still in."""
         self.get_failure(self.handler.forget(self.alice_ID, self.room_id), SynapseError)
 
     def test_rejoin_forgotten_by_user(self) -> None: