diff --git a/reactos/include/ndk/rtlfuncs.h b/reactos/include/ndk/rtlfuncs.h
index c0a205c473f..36f5ecfcc80 100644
--- a/reactos/include/ndk/rtlfuncs.h
+++ b/reactos/include/ndk/rtlfuncs.h
@@ -4419,6 +4419,17 @@ RtlCloneMemoryStream(
 
 #endif // NTOS_MODE_USER
 
+NTSYSAPI
+NTSTATUS
+NTAPI
+RtlFindActivationContextSectionGuid(
+    ULONG flags,
+    const GUID *extguid,
+    ULONG section_kind,
+    const GUID *guid,
+    void *ptr
+);
+
 #ifdef __cplusplus
 }
 #endif