diff --git a/lime/_backend/html5/HTML5Window.hx b/lime/_backend/html5/HTML5Window.hx
index 4aa03e2d9..d7e62ca63 100644
--- a/lime/_backend/html5/HTML5Window.hx
+++ b/lime/_backend/html5/HTML5Window.hx
@@ -224,7 +224,7 @@ class HTML5Window {
 			
 		} else {
 			
-			parent.onMouseWheel.dispatch (untyped event.deltaX, untyped event.deltaY);
+			parent.onMouseWheel.dispatch (untyped event.deltaX, - untyped event.deltaY);
 			
 		}