diff --git a/lib/OpenLayers/Handler/MouseWheel.js b/lib/OpenLayers/Handler/MouseWheel.js
index 144bb285d9..007a42f887 100644
--- a/lib/OpenLayers/Handler/MouseWheel.js
+++ b/lib/OpenLayers/Handler/MouseWheel.js
@@ -172,6 +172,9 @@ OpenLayers.Handler.MouseWheel = OpenLayers.Class(OpenLayers.Handler, {
                 
                 if (e.wheelDelta) {
                     delta = e.wheelDelta;
+                    if (window.opera && window.opera.version() < 9.2) {
+                        delta = -delta;
+                    }
                     if (delta % 160 === 0) {
                         // opera have steps of 160 instead of 120
                         delta = delta * 0.75;