diff --git a/src/core/utility/block_heap.h b/src/core/utility/block_heap.h
index ba3b07e..09d7ad7 100644
--- a/src/core/utility/block_heap.h
+++ b/src/core/utility/block_heap.h
@@ -13,6 +13,7 @@
 // limitations under the License.
 #pragma once
 
+#include <cstddef>
 #include <cstdint>
 #include <utility>
 #include <vector>