diff --git a/gst-libs/gst/gl/gl.h b/gst-libs/gst/gl/gl.h
index ed1c6abc55..4aee9c9e16 100644
--- a/gst-libs/gst/gl/gl.h
+++ b/gst-libs/gst/gl/gl.h
@@ -21,6 +21,11 @@
 #ifndef __GST_GL_H__
 #define __GST_GL_H__
 
+#ifndef GST_USE_UNSTABLE_API
+#warning "The GL library from gst-plugins-bad is unstable API and may change in future."
+#warning "You can define GST_USE_UNSTABLE_API to avoid this warning."
+#endif
+
 #include <gst/gl/gstgl_fwd.h>
 #include <gst/gl/gstglconfig.h>
 #include <gst/gl/gstglapi.h>