diff --git a/libuavcan/include/uavcan/std.hpp b/libuavcan/include/uavcan/std.hpp
index c04ced0c89..a1e63ea469 100644
--- a/libuavcan/include/uavcan/std.hpp
+++ b/libuavcan/include/uavcan/std.hpp
@@ -7,6 +7,7 @@
 
 #include <uavcan/build_config.hpp>
 #include <cstdarg>
+#include <cstddef>
 
 #if !defined(UAVCAN_CPP_VERSION) || !defined(UAVCAN_CPP11)
 # error UAVCAN_CPP_VERSION