diff --git a/roomserver/internal/query/query.go b/roomserver/internal/query/query.go
index 0fe0f4f27..b56b41bdd 100644
--- a/roomserver/internal/query/query.go
+++ b/roomserver/internal/query/query.go
@@ -230,6 +230,31 @@ func (r *Queryer) QueryMembershipForSenderID(
 	senderID spec.SenderID,
 	response *api.QueryMembershipForUserResponse,
 ) error {
+	return r.queryMembershipForOptionalSenderID(ctx, roomID, &senderID, response)
+}
+
+// QueryMembershipForUser implements api.RoomserverInternalAPI
+func (r *Queryer) QueryMembershipForUser(
+	ctx context.Context,
+	request *api.QueryMembershipForUserRequest,
+	response *api.QueryMembershipForUserResponse,
+) error {
+	roomID, err := spec.NewRoomID(request.RoomID)
+	if err != nil {
+		return err
+	}
+	senderID, err := r.QuerySenderIDForUser(ctx, *roomID, request.UserID)
+	if err != nil {
+		return err
+	}
+
+	return r.queryMembershipForOptionalSenderID(ctx, *roomID, senderID, response)
+}
+
+// Query membership information for provided sender ID and room ID
+//
+// If sender ID is nil, then act as if the provided sender is not a member of the room.
+func (r *Queryer) queryMembershipForOptionalSenderID(ctx context.Context, roomID spec.RoomID, senderID *spec.SenderID, response *api.QueryMembershipForUserResponse) error {
 	info, err := r.DB.RoomInfo(ctx, roomID.String())
 	if err != nil {
 		return err
@@ -240,7 +265,11 @@ func (r *Queryer) QueryMembershipForSenderID(
 	}
 	response.RoomExists = true
 
-	membershipEventNID, stillInRoom, isRoomforgotten, err := r.DB.GetMembership(ctx, info.RoomNID, senderID)
+	if senderID == nil {
+		return nil
+	}
+
+	membershipEventNID, stillInRoom, isRoomforgotten, err := r.DB.GetMembership(ctx, info.RoomNID, *senderID)
 	if err != nil {
 		return err
 	}
@@ -268,24 +297,6 @@ func (r *Queryer) QueryMembershipForSenderID(
 	return err
 }
 
-// QueryMembershipForUser implements api.RoomserverInternalAPI
-func (r *Queryer) QueryMembershipForUser(
-	ctx context.Context,
-	request *api.QueryMembershipForUserRequest,
-	response *api.QueryMembershipForUserResponse,
-) error {
-	roomID, err := spec.NewRoomID(request.RoomID)
-	if err != nil {
-		return err
-	}
-	senderID, err := r.QuerySenderIDForUser(ctx, *roomID, request.UserID)
-	if err != nil {
-		return err
-	}
-
-	return r.QueryMembershipForSenderID(ctx, *roomID, *senderID, response)
-}
-
 // QueryMembershipAtEvent returns the known memberships at a given event.
 // If the state before an event is not known, an empty list will be returned
 // for that event instead.