diff --git a/widget/os2/nsWindow.cpp b/widget/os2/nsWindow.cpp
index bf159848367..a8245bd80de 100644
--- a/widget/os2/nsWindow.cpp
+++ b/widget/os2/nsWindow.cpp
@@ -2768,6 +2768,7 @@ bool nsWindow::DispatchKeyEvent(MPARAM mp1, MPARAM mp2)
   event.InitBasicModifiers(fsFlags & KC_CTRL, fsFlags & KC_ALT,
                            fsFlags & KC_SHIFT, false);
   event.charCode  = 0;
+  event.mIsRepeat = event.message == NS_KEY_DOWN && CHAR3FROMMP(mp1) != 0;
 
   // Check for a scroll mouse event vs. a keyboard event.  The way we know
   // this is that the repeat count is 0 and the key is not physically down.