diff --git a/js/modal.js b/js/modal.js
index c757ef2..d1b8ff3 100644
--- a/js/modal.js
+++ b/js/modal.js
@@ -311,6 +311,10 @@
       // button by the show() function called above.)
       $('#modal-content :focusable:first').focus();
     }
+
+    // Trigger a window resize after 100 milliseconds to ensure that the modal is centered properly.
+    // See https://www.drupal.org/node/1803104
+    setTimeout(function() { $(window).trigger('resize'); }, 100);
   }
 
   /**