diff --git a/libs/libc/wchar/CMakeLists.txt b/libs/libc/wchar/CMakeLists.txt
index 0766f27a429..1dc2619fb6a 100644
--- a/libs/libc/wchar/CMakeLists.txt
+++ b/libs/libc/wchar/CMakeLists.txt
@@ -58,4 +58,5 @@ target_sources(
           lib_wcsncpy.c
           lib_wcsncmp.c
           lib_wcscspn.c
-          lib_wcspbrk.c)
+          lib_wcspbrk.c
+          lib_wcsspn.c)
diff --git a/libs/libc/wchar/Make.defs b/libs/libc/wchar/Make.defs
index 11693e20baf..5fb616514ff 100644
--- a/libs/libc/wchar/Make.defs
+++ b/libs/libc/wchar/Make.defs
@@ -28,7 +28,7 @@ CSRCS += lib_wcstoull.c lib_wcstold.c lib_wcstof.c lib_wcstod.c
 CSRCS += lib_swprintf.c lib_mbsnrtowcs.c lib_wcsnrtombs.c lib_mbsinit.c
 CSRCS += lib_mbrlen.c lib_mbsrtowcs.c lib_wcsrtombs.c lib_wcscpy.c
 CSRCS += lib_wcscat.c lib_wcslcat.c lib_wcsncat.c lib_wcsrchr.c lib_wcschr.c
-CSRCS += lib_wcsncpy.c lib_wcsncmp.c lib_wcscspn.c lib_wcspbrk.c
+CSRCS += lib_wcsncpy.c lib_wcsncmp.c lib_wcscspn.c lib_wcspbrk.c lib_wcsspn.c
 
 # Add the wchar directory to the build
 
diff --git a/libs/libc/wchar/lib_wcsspn.c b/libs/libc/wchar/lib_wcsspn.c
new file mode 100644
index 00000000000..54f59de426d
--- /dev/null
+++ b/libs/libc/wchar/lib_wcsspn.c
@@ -0,0 +1,58 @@
+/****************************************************************************
+ * libs/libc/wchar/lib_wcsspn.c
+ *
+ * Copyright © 2005-2014 Rich Felker, et al.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <wchar.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name:  wcsspn
+ *
+ * Description:
+ *    Get span of character set in wide string
+ *
+ * Input Parameters:
+ *   s - the wide string to be scanned
+ *   c - wide string containing the characters to match
+ *
+ * Returned Value:
+ *   The length of the initial portion of "s" which consists only of wide
+ *   characters that are part of "c"
+ *
+ ****************************************************************************/
+
+size_t wcsspn(FAR const wchar_t *s, FAR const wchar_t *c)
+{
+  FAR const wchar_t *a;
+  for (a = s; *s && wcschr(c, *s); s++);
+  return s - a;
+}