diff --git a/include/xrpl/telemetry/SpanGuard.h b/include/xrpl/telemetry/SpanGuard.h
index 51261e17b2..653590e945 100644
--- a/include/xrpl/telemetry/SpanGuard.h
+++ b/include/xrpl/telemetry/SpanGuard.h
@@ -122,6 +122,7 @@
       exposed — all interaction goes through the public methods.
 */
 
+#include <cstddef>
 #include <cstdint>
 #include <exception>
 #include <memory>