diff --git a/types/ws/index.d.ts b/types/ws/index.d.ts
index d5382ba43c..35f9b16f2b 100644
--- a/types/ws/index.d.ts
+++ b/types/ws/index.d.ts
@@ -112,6 +112,7 @@ declare namespace WebSocket {
         host?: string;
         port?: number;
         server?: http.Server | https.Server;
+        backlog?: number;
         verifyClient?: VerifyClientCallbackAsync | VerifyClientCallbackSync;
         handleProtocols?: any;
         path?: string;