diff --git a/types/express-session/index.d.ts b/types/express-session/index.d.ts
index 29d2b4fbbc..0728ff7624 100644
--- a/types/express-session/index.d.ts
+++ b/types/express-session/index.d.ts
@@ -64,6 +64,7 @@ declare namespace session {
     proxy?: boolean;
     saveUninitialized?: boolean;
     unset?: string;
+    sameSite?: boolean | string;
   }
 
   interface BaseMemoryStore {