diff --git a/types/matrix-js-sdk/index.d.ts b/types/matrix-js-sdk/index.d.ts
index f59be84871..5f7a4315a5 100644
--- a/types/matrix-js-sdk/index.d.ts
+++ b/types/matrix-js-sdk/index.d.ts
@@ -231,7 +231,7 @@ export class MatrixClient extends EventEmitter {
   getIdentityServerUrl(stripProto: boolean): string;
   getIgnoredUsers(): string[];
   getJoinedGroups(): Promise<object[]>;
-  getJoinedRoomMembers(roomId: string): Promise<object[]>;
+  getJoinedRoomMembers(roomId: string): Promise<object>;
   getJoinedRooms(): Promise<object[]>;
   getKeyBackupEnabled(): boolean;
   getKeyBackupVersion(): Promise<null | object>;