diff --git a/event.c b/event.c
index 8ba4f04e4..1917f6535 100644
--- a/event.c
+++ b/event.c
@@ -359,11 +359,19 @@ event_handle_widget_motionnotify(void *object,
             luaA_object_push(globalconf.L, *mouse_over);
             luaA_object_emit_signal(globalconf.L, -1, "mouse::leave", 0);
             lua_pop(globalconf.L, 1);
+
+            luaA_object_unref(globalconf.L, *mouse_over);
+            *mouse_over = NULL;
         }
         if(widget)
         {
-            /* emit mouse::enter signal on new widget and register it */
+            /* Get a ref on this widget so that it can't be unref'd from
+             * underneath us (-> invalid pointer dereference). */
+            luaA_object_push(globalconf.L, widget);
+            luaA_object_ref(globalconf.L, -1);
             *mouse_over = widget;
+
+            /* emit mouse::enter signal on new widget */
             luaA_object_push(globalconf.L, widget);
             luaA_object_emit_signal(globalconf.L, -1, "mouse::enter", 0);
             lua_pop(globalconf.L, 1);
@@ -435,7 +443,7 @@ event_handle_leavenotify(void *data __attribute__ ((unused)),
             /* emit mouse::leave signal on widget the mouse was over */
             luaA_object_emit_signal(globalconf.L, -1, "mouse::leave", 0);
             lua_pop(globalconf.L, 1);
-            wibox->mouse_over = NULL;
+            wibox_clear_mouse_over(wibox);
         }
 
         luaA_object_push(globalconf.L, wibox);
diff --git a/wibox.c b/wibox.c
index 88a2396a9..689c81f2f 100644
--- a/wibox.c
+++ b/wibox.c
@@ -59,7 +59,7 @@ static void
 wibox_need_update(wibox_t *wibox)
 {
     wibox->need_update = true;
-    wibox->mouse_over = NULL;
+    wibox_clear_mouse_over(wibox);
 }
 
 static int
@@ -619,6 +619,19 @@ wibox_refresh(void)
     }
 }
 
+/** Clear the wibox' mouse_over pointer.
+ * \param wibox The wibox.
+ */
+void
+wibox_clear_mouse_over(wibox_t *wibox)
+{
+    if (wibox->mouse_over)
+    {
+        luaA_object_unref(globalconf.L, wibox->mouse_over);
+        wibox->mouse_over = NULL;
+    }
+}
+
 /** Set a wibox visible or not.
  * \param L The Lua VM state.
  * \param udx The wibox.
@@ -631,7 +644,7 @@ wibox_set_visible(lua_State *L, int udx, bool v)
     if(v != wibox->visible)
     {
         wibox->visible = v;
-        wibox->mouse_over = NULL;
+        wibox_clear_mouse_over(wibox);
 
         if(wibox->screen)
         {
@@ -704,7 +717,7 @@ wibox_detach(lua_State *L, int udx)
         /* restore visibility */
         wibox->visible = v;
 
-        wibox->mouse_over = NULL;
+        wibox_clear_mouse_over(wibox);
 
         wibox_wipe(wibox);
 
diff --git a/wibox.h b/wibox.h
index fe7050a96..f642ac663 100644
--- a/wibox.h
+++ b/wibox.h
@@ -117,5 +117,7 @@ void wibox_class_setup(lua_State *);
 
 lua_class_t wibox_class;
 
+void wibox_clear_mouse_over(wibox_t *);
+
 #endif
 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=80