diff --git a/dlls/winhttp/main.c b/dlls/winhttp/main.c
index 2915d3b1b17..10a02b78547 100644
--- a/dlls/winhttp/main.c
+++ b/dlls/winhttp/main.c
@@ -270,3 +270,14 @@ BOOL WINAPI WinHttpTimeFromSystemTime (CONST SYSTEMTIME* pst, LPWSTR pwszTime)
     SetLastError(ERROR_NOT_SUPPORTED);
     return FALSE;
 }
+
+/***********************************************************************
+ *          WinHttpTimeToSystemTime (winhttp.@)
+ */
+BOOL WINAPI WinHttpTimeToSystemTime (LPCWSTR pwszTime, SYSTEMTIME* pst)
+{
+    FIXME("(%s, %p): stub\n", debugstr_w(pwszTime), pst);
+
+    SetLastError(ERROR_NOT_SUPPORTED);
+    return FALSE;
+}
diff --git a/dlls/winhttp/winhttp.spec b/dlls/winhttp/winhttp.spec
index 24af2e01559..c0938982883 100644
--- a/dlls/winhttp/winhttp.spec
+++ b/dlls/winhttp/winhttp.spec
@@ -27,5 +27,5 @@
 @ stub WinHttpSetStatusCallback
 @ stub WinHttpSetTimeouts
 @ stdcall WinHttpTimeFromSystemTime(ptr ptr)
-@ stub WinHttpTimeToSystemTime
+@ stdcall WinHttpTimeToSystemTime(wstr ptr)
 @ stdcall WinHttpWriteData(ptr ptr long ptr)