diff --git a/dlls/ntdll/ntdll.spec b/dlls/ntdll/ntdll.spec
index 7a346f2db8c..bd088f3f99d 100644
--- a/dlls/ntdll/ntdll.spec
+++ b/dlls/ntdll/ntdll.spec
@@ -950,6 +950,7 @@ debug_channels (aspi atom cdrom console ddraw debug delayhlp dll dosfs dosmem
 @ cdecl -noimport strspn(str str) strspn
 @ cdecl -noimport strstr(str str) strstr
 @ cdecl -noimport strtol(str ptr long) strtol
+@ cdecl -noimport strtoul(str ptr long) strtoul
 @ varargs swprintf(wstr wstr) NTDLL_swprintf
 @ cdecl -noimport tan(double) tan
 @ cdecl tolower(long) tolower
@@ -973,7 +974,7 @@ debug_channels (aspi atom cdrom console ddraw debug delayhlp dll dosfs dosmem
 @ cdecl wcstok(wstr wstr) NTDLL_wcstok
 @ cdecl wcstol(wstr ptr long) NTDLL_wcstol
 @ cdecl wcstombs(ptr ptr long) NTDLL_wcstombs
-@ stub wcstoul
+@ cdecl wcstoul(wstr ptr long) NTDLL_wcstoul
 @ stub NtAddAtom
 @ stub NtDeleteAtom
 @ stub NtFindAtom
diff --git a/dlls/ntdll/wcstring.c b/dlls/ntdll/wcstring.c
index a2842fdbb58..99df7401434 100644
--- a/dlls/ntdll/wcstring.c
+++ b/dlls/ntdll/wcstring.c
@@ -288,6 +288,21 @@ INT __cdecl NTDLL_wcstol(LPCWSTR s,LPWSTR *end,INT base)
 }
 
 
+/*********************************************************************
+ *                  wcstoul  (NTDLL.@)
+ * Like strtoul, but for wide character strings.
+ */
+INT __cdecl NTDLL_wcstoul(LPCWSTR s,LPWSTR *end,INT base)
+{
+    LPSTR sA = HEAP_strdupWtoA(GetProcessHeap(),0,s),endA;
+    INT	ret = strtoul(sA,&endA,base);
+
+    HeapFree(GetProcessHeap(),0,sA);
+    if (end) *end = ((LPWSTR)s)+(endA-sA); /* pointer magic checked. */
+    return ret;
+}
+
+
 /*********************************************************************
  *           iswctype    (NTDLL.@)
  */