diff --git a/CLI/Repl.cpp b/CLI/Repl.cpp
index cee92c21..83060f5b 100644
--- a/CLI/Repl.cpp
+++ b/CLI/Repl.cpp
@@ -21,6 +21,8 @@
 #include <fcntl.h>
 #endif
 
+#include <locale.h>
+
 LUAU_FASTFLAG(DebugLuauTimeTracing)
 
 enum class CliMode