diff --git a/project/common.mk b/project/common.mk
index 49fdcae..af8cf6b 100644
--- a/project/common.mk
+++ b/project/common.mk
@@ -1,6 +1,7 @@
 API_SRCS = \
 	src/u16_mbsinit.c \
 	src/u16_mbrtowc.c \
+	src/u16_mbstowcs.c \
 
 INTERNAL_SRCS = \
 
diff --git a/src/u16_mbstowcs.c b/src/u16_mbstowcs.c
new file mode 100644
index 0000000..8b84379
--- /dev/null
+++ b/src/u16_mbstowcs.c
@@ -0,0 +1,36 @@
+/*******************************************************************/
+/*  u16ports: u16 variants of wide character string functions.     */
+/*  Copyright (C) 2017  Z. Gilboa                                  */
+/*  Released under the Standard MIT License; see COPYING.U16PORTS. */
+/*******************************************************************/
+
+#include <wchar.h>
+#include <uchar.h>
+#include <u16ports/u16ports.h>
+
+size_t u16_mbstowcs(uint16_t * dst, const char * src, size_t len)
+{
+	size_t		nbytes;
+	uint16_t *	wch;
+	mbstate_t	st = {0};
+
+	for (wch=dst; len; src+=nbytes) {
+		if ((nbytes = mbrtoc16(wch,src,4,&st)) == (size_t)-1) {
+			return (size_t)(-1);
+
+		} else if (nbytes == 0) {
+			return wch - dst;
+
+		} else if (nbytes == (size_t)-3) {
+			nbytes = 0;
+			len--;
+			wch++;
+
+		} else {
+			len--;
+			wch++;
+		}
+	}
+
+	return wch - dst;
+}