diff --git a/src/xwidget.c b/src/xwidget.c
index a53d43016a8..b6f1780927e 100644
--- a/src/xwidget.c
+++ b/src/xwidget.c
@@ -3354,6 +3354,7 @@ lower_frame_xwidget_views (struct frame *f)
 }
 #endif
 
+#ifndef NS_IMPL_COCOA
 void
 kill_frame_xwidget_views (struct frame *f)
 {
@@ -3370,6 +3371,7 @@ kill_frame_xwidget_views (struct frame *f)
   for (; CONSP (rem); rem = XCDR (rem))
     Fdelete_xwidget_view (XCAR (rem));
 }
+#endif
 
 static void
 kill_xwidget (struct xwidget *xw)
diff --git a/src/xwidget.h b/src/xwidget.h
index ef56dfa7c5a..ab60b9ed34f 100644
--- a/src/xwidget.h
+++ b/src/xwidget.h
@@ -200,7 +200,9 @@ struct xwidget_view *xwidget_view_from_window (Window wdesc);
 void xwidget_expose (struct xwidget_view *xv);
 extern void lower_frame_xwidget_views (struct frame *f);
 #endif
+#ifndef NS_IMPL_COCOA
 extern void kill_frame_xwidget_views (struct frame *f);
+#endif
 #ifdef HAVE_X_WINDOWS
 extern void xwidget_button (struct xwidget_view *, bool, int,
 			    int, int, int, Time);