diff --git a/express-jwt/express-jwt.d.ts b/express-jwt/express-jwt.d.ts
index 2afa16dcc..1aec6606f 100644
--- a/express-jwt/express-jwt.d.ts
+++ b/express-jwt/express-jwt.d.ts
@@ -20,7 +20,7 @@ declare module "express-jwt" {
 
     namespace jwt {
         export interface Options {
-            secret: string|ICallback;
+            secret: string|Buffer|ICallback;
             userProperty?: string;
             skip?: string[];
             credentialsRequired?: boolean;