diff --git a/hermit/tools/proxy.c b/hermit/tools/proxy.c
index d7d5789cb..7358c0c01 100644
--- a/hermit/tools/proxy.c
+++ b/hermit/tools/proxy.c
@@ -33,6 +33,7 @@
 #include <signal.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <sched.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/wait.h>