diff --git a/src/headers/lex.hpp b/src/headers/lex.hpp
index baed249..6f97672 100644
--- a/src/headers/lex.hpp
+++ b/src/headers/lex.hpp
@@ -1,6 +1,7 @@
 #ifndef YERBACON_LEX_H
 #define YERBACON_LEX_H
 
+#include <vector>
 #include "Yerbacon.hpp"
 #include <limits>
 #include <ostream>