diff --git a/src/util/subprocess.h b/src/util/subprocess.h
index ba274dfb471..d013d47432b 100644
--- a/src/util/subprocess.h
+++ b/src/util/subprocess.h
@@ -65,7 +65,7 @@ Documentation for C++ subprocessing library.
 
 extern "C" {
 #ifdef __USING_WINDOWS__
-  #include <Windows.h>
+  #include <windows.h>
   #include <io.h>
   #include <cwchar>