diff --git a/src/xenia/base/fuzzy.cc b/src/xenia/base/fuzzy.cc
index dca062e66..6d047dc6d 100644
--- a/src/xenia/base/fuzzy.cc
+++ b/src/xenia/base/fuzzy.cc
@@ -9,6 +9,7 @@
 
 #include "xenia/base/fuzzy.h"
 
+#include <cctype>
 #include <cstring>
 #include <iostream>