diff --git a/encoding/textpb/doc.go b/encoding/textpb/doc.go
new file mode 100644
index 0000000..650d585
--- /dev/null
+++ b/encoding/textpb/doc.go
@@ -0,0 +1,8 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package textpb marshals and unmarshals protocol buffer messages as the
+// textproto format.
+
+package textpb