diff --git a/socket.io/socket.io.d.ts b/socket.io/socket.io.d.ts
index 8d137d7af..3c85d7351 100644
--- a/socket.io/socket.io.d.ts
+++ b/socket.io/socket.io.d.ts
@@ -47,7 +47,7 @@ interface SocketNamespace {
 	send(data: any): any;
 	emit(ev: any, ...data:any[]): Socket;
 	socket(sid: any, readable: boolean): Socket;
-	authorization(fn: Function);
+	authorization(fn: Function): SocketNamespace;
 }
 
 interface SocketManager {