diff --git a/test/testsupport/resources_dir_flag.cc b/test/testsupport/resources_dir_flag.cc
index a6ab3b537b..87a449a401 100644
--- a/test/testsupport/resources_dir_flag.cc
+++ b/test/testsupport/resources_dir_flag.cc
@@ -10,6 +10,8 @@
 
 #include "test/testsupport/resources_dir_flag.h"
 
+#include "absl/flags/flag.h"
+
 ABSL_FLAG(std::string,
           resources_dir,
           "",
diff --git a/test/testsupport/resources_dir_flag.h b/test/testsupport/resources_dir_flag.h
index 055cc82546..7d6f192d9b 100644
--- a/test/testsupport/resources_dir_flag.h
+++ b/test/testsupport/resources_dir_flag.h
@@ -13,7 +13,7 @@
 #ifndef TEST_TESTSUPPORT_RESOURCES_DIR_FLAG_H__
 #define TEST_TESTSUPPORT_RESOURCES_DIR_FLAG_H__
 
-#include "absl/flags/flag.h"
+#include "absl/flags/declare.h"
 
 ABSL_DECLARE_FLAG(std::string, resources_dir);