diff --git a/socket.io-client/index.d.ts b/socket.io-client/index.d.ts
index f4aef879a8..0859c58e08 100644
--- a/socket.io-client/index.d.ts
+++ b/socket.io-client/index.d.ts
@@ -611,6 +611,11 @@ declare namespace SocketIOClient {
 		 */
 		onlyBinaryUpgrades?: boolean;
 
+		/**
+		 * Header options for Node.js client
+		 */
+		extraHeaders?: Object;
+
 		/**
 		 * (SSL) Certificate, Private key and CA certificates to use for SSL.
 		 * Can be used in Node.js client environment to manually specify