diff --git a/project/common.mk b/project/common.mk
index 66ff3ab..3115329 100644
--- a/project/common.mk
+++ b/project/common.mk
@@ -4,6 +4,7 @@ API_SRCS = \
 	src/u16_mbstowcs.c \
 	src/u16_wcstombs.c \
 	src/u16_wcslen.c \
+	src/u16_wcsnlen.c \
 
 INTERNAL_SRCS = \
 
diff --git a/src/u16_wcsnlen.c b/src/u16_wcsnlen.c
new file mode 100644
index 0000000..d155f89
--- /dev/null
+++ b/src/u16_wcsnlen.c
@@ -0,0 +1,19 @@
+/*******************************************************************/
+/*  u16ports: u16 variants of wide character string functions.     */
+/*  Copyright (C) 2017  Z. Gilboa                                  */
+/*  Released under the Standard MIT License; see COPYING.U16PORTS. */
+/*******************************************************************/
+
+#include <stdint.h>
+#include <u16ports/u16ports.h>
+
+size_t u16_wcsnlen(const uint16_t * src, size_t len)
+{
+	const uint16_t * wch = src;
+	const uint16_t * cap = &src[len];
+
+	for (; (wch < cap) && *wch; )
+		wch++;
+
+	return wch - src;
+}