diff --git a/term.go b/term.go
index b7520fb..ea5db93 100644
--- a/term.go
+++ b/term.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build aix darwin dragonfly freebsd linux,!appengine netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd linux,!appengine netbsd openbsd os400 solaris
 
 // Package terminal provides support functions for dealing with terminals, as
 // commonly found on UNIX systems.
diff --git a/term_nosyscall6.go b/term_nosyscall6.go
index 1e12878..df92339 100644
--- a/term_nosyscall6.go
+++ b/term_nosyscall6.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build aix solaris
+// +build aix os400 solaris
 
 package readline
 
diff --git a/utils_unix.go b/utils_unix.go
index d1caecb..fc49492 100644
--- a/utils_unix.go
+++ b/utils_unix.go
@@ -1,4 +1,4 @@
-// +build aix darwin dragonfly freebsd linux,!appengine netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd linux,!appengine netbsd openbsd os400 solaris
 
 package readline