diff --git a/testing/mochitest/tests/SimpleTest/EventUtils.js b/testing/mochitest/tests/SimpleTest/EventUtils.js
index cad43966d91d..9df9dd87cbc9 100644
--- a/testing/mochitest/tests/SimpleTest/EventUtils.js
+++ b/testing/mochitest/tests/SimpleTest/EventUtils.js
@@ -408,7 +408,7 @@ function synthesizeTouchAtPoint(left, top, aEvent, aWindow = window)
   if (utils) {
     var id = aEvent.id || utils.DEFAULT_TOUCH_POINTER_ID;
     var rx = aEvent.rx || 1;
-    var ry = aEvent.rx || 1;
+    var ry = aEvent.ry || 1;
     var angle = aEvent.angle || 0;
     var force = aEvent.force || 1;
     var modifiers = _parseModifiers(aEvent, aWindow);