diff --git a/miniz_zip.c b/miniz_zip.c
index dce07fe..e1e0d47 100644
--- a/miniz_zip.c
+++ b/miniz_zip.c
@@ -40,19 +40,40 @@ extern "C" {
 #include <sys/stat.h>
 
 #if defined(_MSC_VER) || defined(__MINGW64__)
+
+#define WIN32_LEAN_AND_MEAN
+#include <Windows.h>
+
+static WCHAR* mz_utf8z_to_widechar(const char* str)
+{
+  int reqChars = MultiByteToWideChar(CP_UTF8, 0, str, -1, NULL, 0);
+  WCHAR* wStr = (WCHAR*)malloc(reqChars * sizeof(WCHAR));
+  MultiByteToWideChar(CP_UTF8, 0, str, -1, wStr, sizeof(WCHAR) * reqChars);
+  return wStr;
+}
+
 static FILE *mz_fopen(const char *pFilename, const char *pMode)
 {
-    FILE *pFile = NULL;
-    fopen_s(&pFile, pFilename, pMode);
-    return pFile;
+  WCHAR* wFilename = mz_utf8z_to_widechar(pFilename);
+  WCHAR* wMode = mz_utf8z_to_widechar(pMode);
+  FILE* pFile = NULL;
+  errno_t err = _wfopen_s(&pFile, wFilename, wMode);
+  free(wFilename);
+  free(wMode);
+  return err ? NULL : pFile;
 }
+
 static FILE *mz_freopen(const char *pPath, const char *pMode, FILE *pStream)
 {
-    FILE *pFile = NULL;
-    if (freopen_s(&pFile, pPath, pMode, pStream))
-        return NULL;
-    return pFile;
+  WCHAR* wPath = mz_utf8z_to_widechar(pPath);
+  WCHAR* wMode = mz_utf8z_to_widechar(pMode);
+  FILE* pFile = NULL;
+  errno_t err = _wfreopen_s(&pFile, wPath, wMode, pStream);
+  free(wPath);
+  free(wMode);
+  return err ? NULL : pFile;
 }
+
 #ifndef MINIZ_NO_TIME
 #include <sys/utime.h>
 #endif