diff --git a/src/encoding/json/decode_test.go b/src/encoding/json/decode_test.go
index ab83b81bb3958..127bc494e5d46 100644
--- a/src/encoding/json/decode_test.go
+++ b/src/encoding/json/decode_test.go
@@ -142,7 +142,7 @@ var (
 	umstructXY   = ustructText{unmarshalerText{"x", "y"}}
 
 	ummapType = map[unmarshalerText]bool{}
-	ummapXY   = map[unmarshalerText]bool{unmarshalerText{"x", "y"}: true}
+	ummapXY   = map[unmarshalerText]bool{{"x", "y"}: true}
 )
 
 // Test data structures for anonymous fields.
diff --git a/src/encoding/json/encode.go b/src/encoding/json/encode.go
index 7ebb04c50a949..632c12404a677 100644
--- a/src/encoding/json/encode.go
+++ b/src/encoding/json/encode.go
@@ -641,8 +641,11 @@ func (se *structEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
 		} else {
 			e.WriteByte(',')
 		}
-		e.string(f.name, opts.escapeHTML)
-		e.WriteByte(':')
+		if opts.escapeHTML {
+			e.WriteString(f.nameEscHTML)
+		} else {
+			e.WriteString(f.nameNonEsc)
+		}
 		opts.quoted = f.quoted
 		se.fieldEncs[i](e, fv, opts)
 	}
@@ -1036,6 +1039,9 @@ type field struct {
 	nameBytes []byte                 // []byte(name)
 	equalFold func(s, t []byte) bool // bytes.EqualFold or equivalent
 
+	nameNonEsc  string // `"` + name + `":`
+	nameEscHTML string // `"` + HTMLEscape(name) + `":`
+
 	tag       bool
 	index     []int
 	typ       reflect.Type
@@ -1086,6 +1092,9 @@ func typeFields(t reflect.Type) []field {
 	// Fields found.
 	var fields []field
 
+	// Buffer to run HTMLEscape on field names.
+	var nameEscBuf bytes.Buffer
+
 	for len(next) > 0 {
 		current, next = next, current[:0]
 		count, nextCount = nextCount, map[reflect.Type]int{}
@@ -1152,14 +1161,24 @@ func typeFields(t reflect.Type) []field {
 					if name == "" {
 						name = sf.Name
 					}
-					fields = append(fields, fillField(field{
+					field := fillField(field{
 						name:      name,
 						tag:       tagged,
 						index:     index,
 						typ:       ft,
 						omitEmpty: opts.Contains("omitempty"),
 						quoted:    quoted,
-					}))
+					})
+
+					// Build nameEscHTML and nameNonEsc ahead of time.
+					nameEscBuf.Reset()
+					nameEscBuf.WriteString(`"`)
+					HTMLEscape(&nameEscBuf, field.nameBytes)
+					nameEscBuf.WriteString(`":`)
+					field.nameEscHTML = nameEscBuf.String()
+					field.nameNonEsc = `"` + field.name + `":`
+
+					fields = append(fields, field)
 					if count[f.typ] > 1 {
 						// If there were multiple instances, add a second,
 						// so that the annihilation code will see a duplicate.
diff --git a/src/encoding/json/encode_test.go b/src/encoding/json/encode_test.go
index b90483cf35f91..1b7838c895d11 100644
--- a/src/encoding/json/encode_test.go
+++ b/src/encoding/json/encode_test.go
@@ -995,3 +995,18 @@ func TestMarshalPanic(t *testing.T) {
 	Marshal(&marshalPanic{})
 	t.Error("Marshal should have panicked")
 }
+
+func TestMarshalUncommonFieldNames(t *testing.T) {
+	v := struct {
+		A0, À, Aβ int
+	}{}
+	b, err := Marshal(v)
+	if err != nil {
+		t.Fatal("Marshal:", err)
+	}
+	want := `{"A0":0,"À":0,"Aβ":0}`
+	got := string(b)
+	if got != want {
+		t.Fatalf("Marshal: got %s want %s", got, want)
+	}
+}
diff --git a/src/encoding/json/stream_test.go b/src/encoding/json/stream_test.go
index 83c01d170c0b3..0ed1c9e974754 100644
--- a/src/encoding/json/stream_test.go
+++ b/src/encoding/json/stream_test.go
@@ -93,6 +93,10 @@ func TestEncoderIndent(t *testing.T) {
 func TestEncoderSetEscapeHTML(t *testing.T) {
 	var c C
 	var ct CText
+	var tagStruct struct {
+		Valid   int `json:"<>&#! "`
+		Invalid int `json:"\\"`
+	}
 	for _, tt := range []struct {
 		name       string
 		v          interface{}
@@ -102,6 +106,11 @@ func TestEncoderSetEscapeHTML(t *testing.T) {
 		{"c", c, `"\u003c\u0026\u003e"`, `"<&>"`},
 		{"ct", ct, `"\"\u003c\u0026\u003e\""`, `"\"<&>\""`},
 		{`"<&>"`, "<&>", `"\u003c\u0026\u003e"`, `"<&>"`},
+		{
+			"tagStruct", tagStruct,
+			`{"\u003c\u003e\u0026#! ":0,"Invalid":0}`,
+			`{"<>&#! ":0,"Invalid":0}`,
+		},
 	} {
 		var buf bytes.Buffer
 		enc := NewEncoder(&buf)