diff --git a/lib/libsys/ioctl.2 b/lib/libsys/ioctl.2
--- a/lib/libsys/ioctl.2
+++ b/lib/libsys/ioctl.2
@@ -110,6 +110,8 @@
 system call
 will fail if:
 .Bl -tag -width Er
+.It Bq Er EACCES
+The process does not have permission to call this ioctl.
 .It Bq Er EBADF
 The
 .Fa fd