diff --git a/src/unix/async.c b/src/unix/async.c
index 8ab3c903..6abc8125 100644
--- a/src/unix/async.c
+++ b/src/unix/async.c
@@ -24,6 +24,7 @@
 #include <errno.h>
 #include <assert.h>
 #include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
 static int uv__async_init(uv_loop_t* loop);