diff --git a/src/xinerama.c b/src/xinerama.c
index 06a861f3..fcc3a44b 100644
--- a/src/xinerama.c
+++ b/src/xinerama.c
@@ -14,6 +14,7 @@
 #include <stdbool.h>
 #include <assert.h>
 #include <time.h>
+#include <unistd.h>
 
 #include <xcb/xcb.h>
 #include <xcb/xinerama.h>