diff --git a/testing/test_dart_native_resolver.h b/testing/test_dart_native_resolver.h
index 8b928170d4f..632824142d9 100644
--- a/testing/test_dart_native_resolver.h
+++ b/testing/test_dart_native_resolver.h
@@ -5,6 +5,7 @@
 #ifndef FLUTTER_TESTING_TEST_DART_NATIVE_RESOLVER_H_
 #define FLUTTER_TESTING_TEST_DART_NATIVE_RESOLVER_H_
 
+#include <functional>
 #include <map>
 #include <memory>