diff --git a/src/wayland/meta-wayland-subsurface.c b/src/wayland/meta-wayland-subsurface.c
index 4f2ae6df6..acfc7f8b9 100644
--- a/src/wayland/meta-wayland-subsurface.c
+++ b/src/wayland/meta-wayland-subsurface.c
@@ -104,6 +104,7 @@ is_sibling (MetaWaylandSurface *surface,
             MetaWaylandSurface *sibling)
 {
   return surface != sibling &&
+         surface->committed_state.parent &&
          surface->committed_state.parent == sibling->committed_state.parent;
 }