diff --git a/src/lexer/lexer.hpp b/src/lexer/lexer.hpp
index a3dfac0..0ee47b5 100644
--- a/src/lexer/lexer.hpp
+++ b/src/lexer/lexer.hpp
@@ -1,3 +1,4 @@
+#pragma once
 #include "token/token.hpp"
 
 #include <istream>
diff --git a/src/repl/repl.hpp b/src/repl/repl.hpp
index 9d2c5d7..42cd4a1 100644
--- a/src/repl/repl.hpp
+++ b/src/repl/repl.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <istream>
 #include <ostream>