diff --git a/test/gl_in_mainthread_after_pthread.c b/test/gl_in_mainthread_after_pthread.c
index f000a77b52ead..bbb005c469c81 100644
--- a/test/gl_in_mainthread_after_pthread.c
+++ b/test/gl_in_mainthread_after_pthread.c
@@ -11,6 +11,7 @@
 #include <assert.h>
 #include <emscripten/emscripten.h>
 #include <emscripten/html5.h>
+#include <emscripten/threading.h>
 #include <bits/errno.h>
 #include <stdlib.h>