diff --git a/src/string/nstrdup.c b/src/string/nstrdup.c
new file mode 100644
index 0000000..d634157
--- /dev/null
+++ b/src/string/nstrdup.c
@@ -0,0 +1,22 @@
+/** See the end of this file for copyright and license terms. */
+
+#include "neo/_string.h"
+#include "neo/_types.h"
+
+string *nstrdup(const string *s, error *err)
+{
+	return nstr(s->_data, err);
+}
+
+/*
+ * This file is part of libneo.
+ * Copyright (c) 2021 Fefie <owo@fef.moe>.
+ *
+ * libneo is non-violent software: you may only use, redistribute,
+ * and/or modify it under the terms of the CNPLv6+ as found in
+ * the LICENSE file in the source code root directory or at
+ * <https://git.pixie.town/thufie/CNPL>.
+ *
+ * libneo comes with ABSOLUTELY NO WARRANTY, to the extent
+ * permitted by applicable law.  See the CNPLv6+ for details.
+ */
diff --git a/src/string/string.cmake b/src/string/string.cmake
index 31a854b..61c2468 100644
--- a/src/string/string.cmake
+++ b/src/string/string.cmake
@@ -2,6 +2,7 @@ target_sources(neo PRIVATE
     ./string/nstr.c
     ./string/nstrcat.c
     ./string/nstrcmp.c
+    ./string/nstrdup.c
     ./string/nstrmul.c
     ./string/leftpad.c
     ./string/utf.c