diff --git a/functions/network/setrawcookie.js b/functions/network/setrawcookie.js
index 4e3bb3d810..bd98c33937 100644
--- a/functions/network/setrawcookie.js
+++ b/functions/network/setrawcookie.js
@@ -14,10 +14,10 @@ function setrawcookie(name, value, expires, path, domain, secure) {
   }
 
   if (expires instanceof Date) {
-    expires = expires.toGMTString();
+    expires = expires.toUTCString();
   } else if (typeof expires === 'number') {
     expires = (new Date(expires * 1e3))
-      .toGMTString();
+      .toUTCString();
   }
 
   var r = [name + '=' + value],
@@ -36,4 +36,4 @@ function setrawcookie(name, value, expires, path, domain, secure) {
   }
 
   return secure && r.push('secure'), this.window.document.cookie = r.join(';'), true;
-}
\ No newline at end of file
+}