diff --git a/libc/include/signal.h b/libc/include/signal.h
index a9695b4a..9ef5051b 100644
--- a/libc/include/signal.h
+++ b/libc/include/signal.h
@@ -29,6 +29,7 @@
 
 #include <features.h>
 #include <sortix/signal.h>
+#include <sortix/sigset.h>
 
 __BEGIN_DECLS