diff --git a/support/default_validator/default_validator.cc b/support/default_validator/default_validator.cc
index f70809fd..ca36249a 100644
--- a/support/default_validator/default_validator.cc
+++ b/support/default_validator/default_validator.cc
@@ -7,6 +7,7 @@
 #include <cassert>
 #include <cmath>
 #include <cstdarg>
+#include <tuple>
 
 const int EXIT_AC = 42;
 const int EXIT_WA = 43;