diff --git a/cmd/mungedocs/mungedocs.go b/cmd/mungedocs/mungedocs.go
index b82d1d22f23..0c1fe218912 100644
--- a/cmd/mungedocs/mungedocs.go
+++ b/cmd/mungedocs/mungedocs.go
@@ -40,6 +40,7 @@ var (
 	allMunges = []munge{
 		{"table-of-contents", updateTOC},
 		{"check-links", checkLinks},
+		{"unversioned-warning", updateUnversionedWarning},
 	}
 )
 
diff --git a/cmd/mungedocs/unversioned_warning.go b/cmd/mungedocs/unversioned_warning.go
new file mode 100644
index 00000000000..8939fce4532
--- /dev/null
+++ b/cmd/mungedocs/unversioned_warning.go
@@ -0,0 +1,45 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+var beginUnversionedWarning = "<!-- BEGIN UNVERSIONED_WARNING -->"
+var endUnversionedWarning = "<!-- END UNVERSIONED_WARNING -->"
+var unversionedWarning = `
+<!-- BEGIN STRIP_FOR_RELEASE -->
+
+<h1>*** PLEASE NOTE: This document applies to the HEAD of the source
+tree only. If you are using a released version of Kubernetes, you almost
+certainly want the docs that go with that version.</h1>
+
+<strong>Documentation for specific releases can be found at
+[releases.k8s.io](http://releases.k8s.io).</strong>
+
+<!-- END STRIP_FOR_RELEASE -->
+`
+
+// inserts/updates a warning for unversioned docs
+func updateUnversionedWarning(file string, markdown []byte) ([]byte, error) {
+	lines := splitLines(markdown)
+	if hasLine(lines, "<!-- TAG IS_VERSIONED -->") {
+		// No warnings on release branches
+		return markdown, nil
+	}
+	if !hasMacroBlock(lines, beginUnversionedWarning, endUnversionedWarning) {
+		lines = append([]string{beginUnversionedWarning, endUnversionedWarning}, lines...)
+	}
+	return updateMacroBlock(lines, beginUnversionedWarning, endUnversionedWarning, unversionedWarning)
+}
diff --git a/cmd/mungedocs/unversioned_warning_test.go b/cmd/mungedocs/unversioned_warning_test.go
new file mode 100644
index 00000000000..f9431905386
--- /dev/null
+++ b/cmd/mungedocs/unversioned_warning_test.go
@@ -0,0 +1,64 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestUnversionedWarning(t *testing.T) {
+	warningBlock := beginUnversionedWarning + "\n" + unversionedWarning + "\n" + endUnversionedWarning + "\n"
+	var cases = []struct {
+		in  string
+		out string
+	}{
+		{"", warningBlock},
+		{
+			"Foo\nBar\n",
+			warningBlock + "Foo\nBar\n",
+		},
+		{
+			"Foo\n<!-- TAG IS_VERSIONED -->\nBar",
+			"Foo\n<!-- TAG IS_VERSIONED -->\nBar",
+		},
+		{
+			beginUnversionedWarning + "\n" + endUnversionedWarning + "\n",
+			warningBlock,
+		},
+		{
+			beginUnversionedWarning + "\n" + "something\n" + endUnversionedWarning + "\n",
+			warningBlock,
+		},
+		{
+			"Foo\n" + beginUnversionedWarning + "\n" + endUnversionedWarning + "\nBar\n",
+			"Foo\n" + warningBlock + "Bar\n",
+		},
+		{
+			"Foo\n" + warningBlock + "Bar\n",
+			"Foo\n" + warningBlock + "Bar\n",
+		},
+	}
+	for i, c := range cases {
+		actual, err := updateUnversionedWarning("filename.md", []byte(c.in))
+		assert.NoError(t, err)
+		if string(actual) != c.out {
+			t.Errorf("case[%d]: expected %q got %q", i, c.out, string(actual))
+		}
+	}
+}