diff --git a/include/llmr/util/utf.hpp b/include/llmr/util/utf.hpp
index 8aa85a90a..92da93f01 100644
--- a/include/llmr/util/utf.hpp
+++ b/include/llmr/util/utf.hpp
@@ -8,6 +8,7 @@
 #include <boost/locale.hpp>
 #else
 #include <codecvt>
+#include <locale>
 #endif
 
 namespace llmr {