diff --git a/tests/gtest/avifincrtest.cc b/tests/gtest/avifincrtest.cc
index 6aae233..74307b4 100644
--- a/tests/gtest/avifincrtest.cc
+++ b/tests/gtest/avifincrtest.cc
@@ -5,6 +5,7 @@
 
 #include <fstream>
 #include <iostream>
+#include <string>
 #include <tuple>
 
 #include "avifincrtest_helpers.h"