diff --git a/addons/mail/static/src/js/composer.js b/addons/mail/static/src/js/composer.js
index 6560e76fb13..21a4124ee54 100644
--- a/addons/mail/static/src/js/composer.js
+++ b/addons/mail/static/src/js/composer.js
@@ -130,7 +130,7 @@ var MentionManager = Widget.extend({
     get_listener_selection: function (delimiter) {
         var listener = _.findWhere(this.listeners, {delimiter: delimiter});
         if (listener) {
-            var input_mentions = this.composer.$input.val().match(new RegExp(delimiter+'[^ ]+', 'g'));
+            var input_mentions = this.composer.$input.val().match(new RegExp(delimiter+'[^ ]+(?= | )', 'g'));
             return this._validate_selection(listener.selection, input_mentions);
         }
         return [];
@@ -270,7 +270,7 @@ var MentionManager = Widget.extend({
         // create the regex of all mention's names
         var names = _.pluck(listener.selection, 'name');
         var escaped_names = _.map(names, function (str) {
-            return "("+_.str.escapeRegExp(listener.delimiter+str)+")";
+            return "("+_.str.escapeRegExp(listener.delimiter+str)+")(?= | )";
         });
         var regex_str = escaped_names.join('|');
         // extract matches