diff --git a/centipede/testing/external_target.cc b/centipede/testing/external_target.cc
index 3e1fbdff4..491efb69b 100644
--- a/centipede/testing/external_target.cc
+++ b/centipede/testing/external_target.cc
@@ -22,6 +22,7 @@
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
+#include <functional>
 
 #include "absl/base/nullability.h"
 #include "absl/log/check.h"
diff --git a/centipede/testing/fuzz_target_with_config.cc b/centipede/testing/fuzz_target_with_config.cc
index 93a8379c0..20bd25b2b 100644
--- a/centipede/testing/fuzz_target_with_config.cc
+++ b/centipede/testing/fuzz_target_with_config.cc
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 #include <cstdlib>
+#include <functional>
 #include <string>
 
 #include "absl/base/nullability.h"