diff --git a/include/sharg/validators.hpp b/include/sharg/validators.hpp
index 89ece5ec..88bb4b98 100644
--- a/include/sharg/validators.hpp
+++ b/include/sharg/validators.hpp
@@ -12,6 +12,7 @@
 
 #pragma once
 
+#include <algorithm>
 #include <fstream>
 #include <regex>