diff --git a/src/html/fuzz.go b/src/html/fuzz.go
new file mode 100644
index 00000000000..ffa3e257f40
--- /dev/null
+++ b/src/html/fuzz.go
@@ -0,0 +1,31 @@
+// 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.
+
+// +build gofuzz
+
+package html
+
+import (
+	"fmt"
+)
+
+func Fuzz(data []byte) int {
+	v := string(data)
+
+	e := EscapeString(v)
+	u := UnescapeString(e)
+	if v != u {
+		fmt.Printf("v = %q\n", v)
+		fmt.Printf("e = %q\n", e)
+		fmt.Printf("u = %q\n", u)
+		panic("not equal")
+	}
+
+	// As per the documentation, this isn't always equal to v, so it makes
+	// no sense to check for equality. It can still be interesting to find
+	// panics in it though.
+	EscapeString(UnescapeString(v))
+
+	return 0
+}