diff --git a/gemma/tiled_attention_test.cc b/gemma/tiled_attention_test.cc
index 76af6655..f93338b2 100644
--- a/gemma/tiled_attention_test.cc
+++ b/gemma/tiled_attention_test.cc
@@ -3,6 +3,7 @@
 #include <iostream>
 #include <memory>
 #include <optional>
+#include <string>
 #include <tuple>
 #include <vector>