diff --git a/Userland/Libraries/LibC/wchar.cpp b/Userland/Libraries/LibC/wchar.cpp
index 407958e009..33813a6209 100644
--- a/Userland/Libraries/LibC/wchar.cpp
+++ b/Userland/Libraries/LibC/wchar.cpp
@@ -556,4 +556,10 @@ size_t wcsnrtombs(char*, const wchar_t**, size_t, size_t, mbstate_t*)
     dbgln("FIXME: Implement wcsnrtombs()");
     TODO();
 }
+
+size_t mbsnrtowcs(wchar_t*, const char**, size_t, size_t, mbstate_t*)
+{
+    dbgln("FIXME: Implement mbsnrtowcs()");
+    TODO();
+}
 }
diff --git a/Userland/Libraries/LibC/wchar.h b/Userland/Libraries/LibC/wchar.h
index 31ff44f85a..6abcbb46e6 100644
--- a/Userland/Libraries/LibC/wchar.h
+++ b/Userland/Libraries/LibC/wchar.h
@@ -62,5 +62,6 @@ size_t wcsrtombs(char*, const wchar_t**, size_t, mbstate_t*);
 size_t mbsrtowcs(wchar_t*, const char**, size_t, mbstate_t*);
 int wmemcmp(const wchar_t*, const wchar_t*, size_t);
 size_t wcsnrtombs(char*, const wchar_t**, size_t, size_t, mbstate_t*);
+size_t mbsnrtowcs(wchar_t*, const char**, size_t, size_t, mbstate_t*);
 
 __END_DECLS