diff --git a/lib/kadm5/private.h b/lib/kadm5/private.h
index 43ee5e86f..d93a5957f 100644
--- a/lib/kadm5/private.h
+++ b/lib/kadm5/private.h
@@ -36,6 +36,10 @@
 #ifndef __kadm5_privatex_h__
 #define __kadm5_privatex_h__
 
+#ifdef HAVE_SYS_UN_H
+#include <sys/un.h>
+#endif
+
 struct kadm_func {
     kadm5_ret_t (*chpass_principal) (void *, krb5_principal, int,
 				     int, krb5_key_salt_tuple*, const char*);