diff --git a/reactos/base/system/lsass/lsass.c b/reactos/base/system/lsass/lsass.c
index 1f366efbee5..9fffd8e1412 100644
--- a/reactos/base/system/lsass/lsass.c
+++ b/reactos/base/system/lsass/lsass.c
@@ -28,6 +28,7 @@
 #define NTOS_MODE_USER
 
 #include <ndk/psfuncs.h>
+#include <ndk/rtlfuncs.h>
 
 #include <lsass/lsasrv.h>
 #include <samsrv/samsrv.h>