diff --git a/sanic/cookies.py b/sanic/cookies.py
index 8ad8cbfc..f4cbf6a3 100644
--- a/sanic/cookies.py
+++ b/sanic/cookies.py
@@ -83,6 +83,7 @@ class Cookie(dict):
         "secure": "Secure",
         "httponly": "HttpOnly",
         "version": "Version",
+        "samesite": "SameSite",
     }
     _flags = {'secure', 'httponly'}