diff --git a/src/openrct2/core/CircularBuffer.h b/src/openrct2/core/CircularBuffer.h
index 324fd04c7e..f8d74fbc79 100644
--- a/src/openrct2/core/CircularBuffer.h
+++ b/src/openrct2/core/CircularBuffer.h
@@ -10,6 +10,7 @@
 #pragma once
 
 #include <array>
+#include <cstddef>
 
 template<typename _TType, size_t _TMax> class CircularBuffer
 {