diff --git a/compat/mingw.c b/compat/mingw.c
index 8ee0b6408e..a46a8af8c9 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -2592,6 +2592,9 @@ static void setup_windows_environment(void)
 		if (!tmp && (tmp = getenv("USERPROFILE")))
 			setenv("HOME", tmp, 1);
 	}
+
+	if (!getenv("LC_ALL") && !getenv("LC_CTYPE") && !getenv("LANG"))
+		setenv("LC_CTYPE", "C", 1);
 }
 
 int is_valid_win32_path(const char *path, int allow_literal_nul)