diff --git a/rust/cpp_kernel/extension.cc b/rust/cpp_kernel/extension.cc
index d74081156343c..b9f6a4bb4ceb2 100644
--- a/rust/cpp_kernel/extension.cc
+++ b/rust/cpp_kernel/extension.cc
@@ -5,7 +5,6 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-#include <cstddef>
 #include <cstdint>
 #include <string>
 #include <utility>