diff --git a/source/js/components/petition/petition.jsx b/source/js/components/petition/petition.jsx
index ac3d56a60a8..13ff59db5c5 100644
--- a/source/js/components/petition/petition.jsx
+++ b/source/js/components/petition/petition.jsx
@@ -345,7 +345,7 @@ export default class Petition extends React.Component {
     if (!input) {
       return false;
     }
-    return input.match(/[^@]+@[^@]+/) !== null;
+    return input.match(/[^@]+@[^.@]+(\.[^.@]+)+$/) !== null;
   }
 
   /**