diff --git a/sub/osd_libass.c b/sub/osd_libass.c
index eadb0e8da5..32edf78f96 100644
--- a/sub/osd_libass.c
+++ b/sub/osd_libass.c
@@ -104,6 +104,7 @@ static ASS_Event *add_osd_ass_event(ASS_Track *track, const char *text)
     event->Start = 0;
     event->Duration = 100;
     event->Style = track->default_style;
+    event->ReadOrder = n;
     assert(event->Text == NULL);
     if (text)
         event->Text = strdup(text);