diff --git a/src/data/memory_chunk.h b/src/data/memory_chunk.h
index af71842..64d535e 100644
--- a/src/data/memory_chunk.h
+++ b/src/data/memory_chunk.h
@@ -40,6 +40,7 @@
 #include <algorithm>
 #include <inttypes.h>
 #include <sys/mman.h>
+#include <cstddef>
 
 namespace torrent {
 
diff --git a/src/torrent/common.h b/src/torrent/common.h
index 4ed250f..b7d7b7b 100644
--- a/src/torrent/common.h
+++ b/src/torrent/common.h
@@ -38,6 +38,7 @@
 #define LIBTORRENT_COMMON_H
 
 #include <inttypes.h>
+#include <cstddef>
 
 struct sockaddr;