diff --git a/Userland/Libraries/LibThreading/Mutex.h b/Userland/Libraries/LibThreading/Mutex.h
index 05ef1d1373..44921eab61 100644
--- a/Userland/Libraries/LibThreading/Mutex.h
+++ b/Userland/Libraries/LibThreading/Mutex.h
@@ -7,6 +7,7 @@
 #pragma once
 
 #include <AK/Assertions.h>
+#include <AK/Noncopyable.h>
 #include <AK/Types.h>
 #include <pthread.h>