diff --git a/jsonpb/jsonpb.go b/jsonpb/jsonpb.go
index 69ed7fd..91dcd26 100644
--- a/jsonpb/jsonpb.go
+++ b/jsonpb/jsonpb.go
@@ -79,7 +79,7 @@
 // Marshal marshals a protocol buffer into JSON.
 func (m *Marshaler) Marshal(out io.Writer, pb proto.Message) error {
 	writer := &errWriter{writer: out}
-	return m.marshalObject(writer, pb, "")
+	return m.marshalObject(writer, pb, "", "")
 }
 
 // MarshalToString converts a protocol buffer object to JSON string.
@@ -98,14 +98,15 @@
 func (s int32Slice) Less(i, j int) bool { return s[i] < s[j] }
 func (s int32Slice) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
 
+type wkt interface {
+	XXX_WellKnownType() string
+}
+
 // marshalObject writes a struct to the Writer.
-func (m *Marshaler) marshalObject(out *errWriter, v proto.Message, indent string) error {
+func (m *Marshaler) marshalObject(out *errWriter, v proto.Message, indent, typeURL string) error {
 	s := reflect.ValueOf(v).Elem()
 
 	// Handle well-known types.
-	type wkt interface {
-		XXX_WellKnownType() string
-	}
 	if wkt, ok := v.(wkt); ok {
 		switch wkt.XXX_WellKnownType() {
 		case "DoubleValue", "FloatValue", "Int64Value", "UInt64Value",
@@ -114,6 +115,9 @@
 			//  as the wrapped primitive type, ..."
 			sprop := proto.GetProperties(s.Type())
 			return m.marshalValue(out, sprop.Prop[0], s.Field(0), indent)
+		case "Any":
+			// Any is a bit more involved.
+			return m.marshalAny(out, v, indent)
 		case "Duration":
 			// "Generated output always contains 3, 6, or 9 fractional digits,
 			//  depending on required precision."
@@ -163,6 +167,14 @@
 	}
 
 	firstField := true
+
+	if typeURL != "" {
+		if err := m.marshalTypeURL(out, indent, typeURL); err != nil {
+			return err
+		}
+		firstField = false
+	}
+
 	for i := 0; i < s.NumField(); i++ {
 		value := s.Field(i)
 		valueField := s.Type().Field(i)
@@ -271,6 +283,70 @@
 	}
 }
 
+func (m *Marshaler) marshalAny(out *errWriter, any proto.Message, indent string) error {
+	// "If the Any contains a value that has a special JSON mapping,
+	//  it will be converted as follows: {"@type": xxx, "value": yyy}.
+	//  Otherwise, the value will be converted into a JSON object,
+	//  and the "@type" field will be inserted to indicate the actual data type."
+	v := reflect.ValueOf(any).Elem()
+	turl := v.Field(0).String()
+	val := v.Field(1).Bytes()
+
+	// Only the part of type_url after the last slash is relevant.
+	mname := turl
+	if slash := strings.LastIndex(mname, "/"); slash >= 0 {
+		mname = mname[slash+1:]
+	}
+	mt := proto.MessageType(mname)
+	if mt == nil {
+		return fmt.Errorf("unknown message type %q", mname)
+	}
+	msg := reflect.New(mt.Elem()).Interface().(proto.Message)
+	if err := proto.Unmarshal(val, msg); err != nil {
+		return err
+	}
+
+	if _, ok := msg.(wkt); ok {
+		out.write("{")
+		if m.Indent != "" {
+			out.write("\n")
+		}
+		if err := m.marshalTypeURL(out, indent, turl); err != nil {
+			return err
+		}
+		m.writeSep(out)
+		out.write(`"value":`)
+		if err := m.marshalObject(out, msg, indent, ""); err != nil {
+			return err
+		}
+		if m.Indent != "" {
+			out.write("\n")
+			out.write(indent)
+		}
+		out.write("}")
+		return out.err
+	}
+
+	return m.marshalObject(out, msg, indent, turl)
+}
+
+func (m *Marshaler) marshalTypeURL(out *errWriter, indent, typeURL string) error {
+	if m.Indent != "" {
+		out.write(indent)
+		out.write(m.Indent)
+	}
+	out.write(`"@type":`)
+	if m.Indent != "" {
+		out.write(" ")
+	}
+	b, err := json.Marshal(typeURL)
+	if err != nil {
+		return err
+	}
+	out.write(string(b))
+	return out.err
+}
+
 // marshalField writes field description and value to the Writer.
 func (m *Marshaler) marshalField(out *errWriter, prop *proto.Properties, v reflect.Value, indent string) error {
 	if m.Indent != "" {
@@ -358,7 +434,7 @@
 
 	// Handle nested messages.
 	if v.Kind() == reflect.Struct {
-		return m.marshalObject(out, v.Addr().Interface().(proto.Message), indent+m.Indent)
+		return m.marshalObject(out, v.Addr().Interface().(proto.Message), indent+m.Indent, "")
 	}
 
 	// Handle maps.
@@ -478,6 +554,8 @@
 			// encoding/json will turn JSON `null` into Go `nil`,
 			// so we don't have to do any extra work.
 			return unmarshalValue(target.Field(0), inputValue, prop)
+		case "Any":
+			return fmt.Errorf("unmarshaling Any not supported yet")
 		case "Duration":
 			unq, err := strconv.Unquote(string(inputValue))
 			if err != nil {
diff --git a/jsonpb/jsonpb_test.go b/jsonpb/jsonpb_test.go
index b912fae..bed8b30 100644
--- a/jsonpb/jsonpb_test.go
+++ b/jsonpb/jsonpb_test.go
@@ -42,6 +42,7 @@
 
 	pb "github.com/golang/protobuf/jsonpb/jsonpb_test_proto"
 	proto3pb "github.com/golang/protobuf/proto/proto3_proto"
+	anypb "github.com/golang/protobuf/ptypes/any"
 	durpb "github.com/golang/protobuf/ptypes/duration"
 	stpb "github.com/golang/protobuf/ptypes/struct"
 	tspb "github.com/golang/protobuf/ptypes/timestamp"
@@ -339,6 +340,21 @@
 		`{"o_int32":4}`},
 	{"proto2 extension", marshaler, realNumber, realNumberJSON},
 
+	{"Any with message", marshaler, &pb.KnownTypes{An: &anypb.Any{
+		TypeUrl: "something.example.com/jsonpb.Simple",
+		Value: []byte{
+			// &pb.Simple{OBool:true}
+			1 << 3, 1,
+		},
+	}}, `{"an":{"@type":"something.example.com/jsonpb.Simple","oBool":true}}`},
+	{"Any with WKT", marshaler, &pb.KnownTypes{An: &anypb.Any{
+		TypeUrl: "type.googleapis.com/google.protobuf.Duration",
+		Value: []byte{
+			// &durpb.Duration{Seconds: 1, Nanos: 212000000 }
+			1 << 3, 1, // seconds
+			2 << 3, 0x80, 0xba, 0x8b, 0x65, // nanos
+		},
+	}}, `{"an":{"@type":"type.googleapis.com/google.protobuf.Duration","value":"1.212s"}}`},
 	{"Duration", marshaler, &pb.KnownTypes{Dur: &durpb.Duration{Seconds: 3}}, `{"dur":"3.000s"}`},
 	{"Struct", marshaler, &pb.KnownTypes{St: &stpb.Struct{
 		Fields: map[string]*stpb.Value{
diff --git a/jsonpb/jsonpb_test_proto/Makefile b/jsonpb/jsonpb_test_proto/Makefile
index 3f845ba..eeda8ae 100644
--- a/jsonpb/jsonpb_test_proto/Makefile
+++ b/jsonpb/jsonpb_test_proto/Makefile
@@ -30,4 +30,4 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 regenerate:
-	protoc --go_out=Mgoogle/protobuf/duration.proto=github.com/golang/protobuf/ptypes/duration,Mgoogle/protobuf/struct.proto=github.com/golang/protobuf/ptypes/struct,Mgoogle/protobuf/timestamp.proto=github.com/golang/protobuf/ptypes/timestamp,Mgoogle/protobuf/wrappers.proto=github.com/golang/protobuf/ptypes/wrappers:. *.proto
+	protoc --go_out=Mgoogle/protobuf/any.proto=github.com/golang/protobuf/ptypes/any,Mgoogle/protobuf/duration.proto=github.com/golang/protobuf/ptypes/duration,Mgoogle/protobuf/struct.proto=github.com/golang/protobuf/ptypes/struct,Mgoogle/protobuf/timestamp.proto=github.com/golang/protobuf/ptypes/timestamp,Mgoogle/protobuf/wrappers.proto=github.com/golang/protobuf/ptypes/wrappers:. *.proto
diff --git a/jsonpb/jsonpb_test_proto/test_objects.pb.go b/jsonpb/jsonpb_test_proto/test_objects.pb.go
index a1500e5..92edd97 100644
--- a/jsonpb/jsonpb_test_proto/test_objects.pb.go
+++ b/jsonpb/jsonpb_test_proto/test_objects.pb.go
@@ -7,10 +7,11 @@
 import proto "github.com/golang/protobuf/proto"
 import fmt "fmt"
 import math "math"
-import google_protobuf "github.com/golang/protobuf/ptypes/duration"
-import google_protobuf1 "github.com/golang/protobuf/ptypes/struct"
-import google_protobuf2 "github.com/golang/protobuf/ptypes/timestamp"
-import google_protobuf3 "github.com/golang/protobuf/ptypes/wrappers"
+import google_protobuf "github.com/golang/protobuf/ptypes/any"
+import google_protobuf1 "github.com/golang/protobuf/ptypes/duration"
+import google_protobuf2 "github.com/golang/protobuf/ptypes/struct"
+import google_protobuf3 "github.com/golang/protobuf/ptypes/timestamp"
+import google_protobuf4 "github.com/golang/protobuf/ptypes/wrappers"
 
 // Reference imports to suppress errors if they are not otherwise used.
 var _ = proto.Marshal
@@ -546,18 +547,19 @@
 }
 
 type KnownTypes struct {
-	Dur              *google_protobuf.Duration     `protobuf:"bytes,1,opt,name=dur" json:"dur,omitempty"`
-	St               *google_protobuf1.Struct      `protobuf:"bytes,12,opt,name=st" json:"st,omitempty"`
-	Ts               *google_protobuf2.Timestamp   `protobuf:"bytes,2,opt,name=ts" json:"ts,omitempty"`
-	Dbl              *google_protobuf3.DoubleValue `protobuf:"bytes,3,opt,name=dbl" json:"dbl,omitempty"`
-	Flt              *google_protobuf3.FloatValue  `protobuf:"bytes,4,opt,name=flt" json:"flt,omitempty"`
-	I64              *google_protobuf3.Int64Value  `protobuf:"bytes,5,opt,name=i64" json:"i64,omitempty"`
-	U64              *google_protobuf3.UInt64Value `protobuf:"bytes,6,opt,name=u64" json:"u64,omitempty"`
-	I32              *google_protobuf3.Int32Value  `protobuf:"bytes,7,opt,name=i32" json:"i32,omitempty"`
-	U32              *google_protobuf3.UInt32Value `protobuf:"bytes,8,opt,name=u32" json:"u32,omitempty"`
-	Bool             *google_protobuf3.BoolValue   `protobuf:"bytes,9,opt,name=bool" json:"bool,omitempty"`
-	Str              *google_protobuf3.StringValue `protobuf:"bytes,10,opt,name=str" json:"str,omitempty"`
-	Bytes            *google_protobuf3.BytesValue  `protobuf:"bytes,11,opt,name=bytes" json:"bytes,omitempty"`
+	An               *google_protobuf.Any          `protobuf:"bytes,14,opt,name=an" json:"an,omitempty"`
+	Dur              *google_protobuf1.Duration    `protobuf:"bytes,1,opt,name=dur" json:"dur,omitempty"`
+	St               *google_protobuf2.Struct      `protobuf:"bytes,12,opt,name=st" json:"st,omitempty"`
+	Ts               *google_protobuf3.Timestamp   `protobuf:"bytes,2,opt,name=ts" json:"ts,omitempty"`
+	Dbl              *google_protobuf4.DoubleValue `protobuf:"bytes,3,opt,name=dbl" json:"dbl,omitempty"`
+	Flt              *google_protobuf4.FloatValue  `protobuf:"bytes,4,opt,name=flt" json:"flt,omitempty"`
+	I64              *google_protobuf4.Int64Value  `protobuf:"bytes,5,opt,name=i64" json:"i64,omitempty"`
+	U64              *google_protobuf4.UInt64Value `protobuf:"bytes,6,opt,name=u64" json:"u64,omitempty"`
+	I32              *google_protobuf4.Int32Value  `protobuf:"bytes,7,opt,name=i32" json:"i32,omitempty"`
+	U32              *google_protobuf4.UInt32Value `protobuf:"bytes,8,opt,name=u32" json:"u32,omitempty"`
+	Bool             *google_protobuf4.BoolValue   `protobuf:"bytes,9,opt,name=bool" json:"bool,omitempty"`
+	Str              *google_protobuf4.StringValue `protobuf:"bytes,10,opt,name=str" json:"str,omitempty"`
+	Bytes            *google_protobuf4.BytesValue  `protobuf:"bytes,11,opt,name=bytes" json:"bytes,omitempty"`
 	XXX_unrecognized []byte                        `json:"-"`
 }
 
@@ -566,84 +568,91 @@
 func (*KnownTypes) ProtoMessage()               {}
 func (*KnownTypes) Descriptor() ([]byte, []int) { return fileDescriptor1, []int{7} }
 
-func (m *KnownTypes) GetDur() *google_protobuf.Duration {
+func (m *KnownTypes) GetAn() *google_protobuf.Any {
+	if m != nil {
+		return m.An
+	}
+	return nil
+}
+
+func (m *KnownTypes) GetDur() *google_protobuf1.Duration {
 	if m != nil {
 		return m.Dur
 	}
 	return nil
 }
 
-func (m *KnownTypes) GetSt() *google_protobuf1.Struct {
+func (m *KnownTypes) GetSt() *google_protobuf2.Struct {
 	if m != nil {
 		return m.St
 	}
 	return nil
 }
 
-func (m *KnownTypes) GetTs() *google_protobuf2.Timestamp {
+func (m *KnownTypes) GetTs() *google_protobuf3.Timestamp {
 	if m != nil {
 		return m.Ts
 	}
 	return nil
 }
 
-func (m *KnownTypes) GetDbl() *google_protobuf3.DoubleValue {
+func (m *KnownTypes) GetDbl() *google_protobuf4.DoubleValue {
 	if m != nil {
 		return m.Dbl
 	}
 	return nil
 }
 
-func (m *KnownTypes) GetFlt() *google_protobuf3.FloatValue {
+func (m *KnownTypes) GetFlt() *google_protobuf4.FloatValue {
 	if m != nil {
 		return m.Flt
 	}
 	return nil
 }
 
-func (m *KnownTypes) GetI64() *google_protobuf3.Int64Value {
+func (m *KnownTypes) GetI64() *google_protobuf4.Int64Value {
 	if m != nil {
 		return m.I64
 	}
 	return nil
 }
 
-func (m *KnownTypes) GetU64() *google_protobuf3.UInt64Value {
+func (m *KnownTypes) GetU64() *google_protobuf4.UInt64Value {
 	if m != nil {
 		return m.U64
 	}
 	return nil
 }
 
-func (m *KnownTypes) GetI32() *google_protobuf3.Int32Value {
+func (m *KnownTypes) GetI32() *google_protobuf4.Int32Value {
 	if m != nil {
 		return m.I32
 	}
 	return nil
 }
 
-func (m *KnownTypes) GetU32() *google_protobuf3.UInt32Value {
+func (m *KnownTypes) GetU32() *google_protobuf4.UInt32Value {
 	if m != nil {
 		return m.U32
 	}
 	return nil
 }
 
-func (m *KnownTypes) GetBool() *google_protobuf3.BoolValue {
+func (m *KnownTypes) GetBool() *google_protobuf4.BoolValue {
 	if m != nil {
 		return m.Bool
 	}
 	return nil
 }
 
-func (m *KnownTypes) GetStr() *google_protobuf3.StringValue {
+func (m *KnownTypes) GetStr() *google_protobuf4.StringValue {
 	if m != nil {
 		return m.Str
 	}
 	return nil
 }
 
-func (m *KnownTypes) GetBytes() *google_protobuf3.BytesValue {
+func (m *KnownTypes) GetBytes() *google_protobuf4.BytesValue {
 	if m != nil {
 		return m.Bytes
 	}
@@ -673,68 +682,70 @@
 }
 
 var fileDescriptor1 = []byte{
-	// 1008 bytes of a gzipped FileDescriptorProto
+	// 1031 bytes of a gzipped FileDescriptorProto
 	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x09, 0x6e, 0x88, 0x02, 0xff, 0x74, 0x95, 0xdf, 0x72, 0xdb, 0x44,
-	0x14, 0xc6, 0x2b, 0xad, 0x25, 0xd9, 0xeb, 0x24, 0x98, 0x9d, 0x94, 0xaa, 0x26, 0x80, 0xc6, 0x03,
-	0x45, 0x14, 0xea, 0x0e, 0x8a, 0xc7, 0xc3, 0x14, 0x6e, 0x48, 0x63, 0x28, 0x03, 0x29, 0x33, 0xeb,
-	0x86, 0x5e, 0x7a, 0xe4, 0x78, 0x6d, 0x54, 0x64, 0xad, 0x67, 0x77, 0x45, 0xea, 0x81, 0x8b, 0x3c,
-	0x04, 0xaf, 0x00, 0x8f, 0xc0, 0x25, 0xcf, 0xc6, 0x9c, 0x5d, 0xfd, 0x71, 0xec, 0xf8, 0x2a, 0x3e,
-	0x3a, 0xdf, 0xf9, 0xb2, 0xfa, 0xed, 0xd1, 0x39, 0x98, 0x28, 0x26, 0xd5, 0x84, 0x4f, 0xdf, 0xb0,
-	0x2b, 0x25, 0xfb, 0x2b, 0xc1, 0x15, 0x27, 0xee, 0x1b, 0xc9, 0xb3, 0xd5, 0xb4, 0xfb, 0xe1, 0x82,
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+	0xc7, 0xed, 0x6e, 0x2b, 0xec, 0xd9, 0x2e, 0x14, 0x8d, 0xcb, 0x9a, 0xfe, 0x7f, 0x0d, 0x42, 0x7e,
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+	0x3f, 0x30, 0x43, 0x7e, 0x50, 0x0e, 0xf9, 0xc1, 0xf3, 0x6c, 0xc5, 0xec, 0x38, 0xa3, 0x5f, 0x10,
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+	0x23, 0xb6, 0xd2, 0xfe, 0x0e, 0x6a, 0x1f, 0x6c, 0x68, 0xcf, 0x70, 0xed, 0x30, 0x5b, 0xc1, 0x77,
+	0x6d, 0x6b, 0x55, 0xdc, 0x5c, 0x6f, 0x43, 0xf8, 0xba, 0xdc, 0x40, 0xcc, 0xd6, 0x8a, 0x0e, 0x88,
+	0x33, 0x9b, 0xa6, 0x08, 0xbe, 0x13, 0x1d, 0x6e, 0x9e, 0x00, 0x07, 0xcd, 0x2f, 0x00, 0x99, 0x81,
+	0x90, 0x3e, 0x21, 0xce, 0x65, 0xaa, 0x71, 0x6d, 0x40, 0xd3, 0xaf, 0xeb, 0x71, 0x64, 0x15, 0xf2,
+	0xcb, 0x54, 0x83, 0x3c, 0x29, 0x56, 0xc9, 0x5d, 0x72, 0x6c, 0xe3, 0x42, 0x9e, 0x8c, 0x86, 0x70,
+	0x9a, 0x7c, 0x34, 0xc4, 0xf5, 0x72, 0xd7, 0x69, 0xce, 0x6f, 0xea, 0xf3, 0xd1, 0x10, 0xed, 0x8f,
+	0x22, 0xdc, 0x39, 0x5b, 0xec, 0x8f, 0xa2, 0xd2, 0xfe, 0x28, 0x42, 0xfb, 0xa3, 0x08, 0x17, 0xd1,
+	0x36, 0xfb, 0x4a, 0x9f, 0xa3, 0xbe, 0x81, 0x6b, 0xa4, 0xbd, 0x05, 0x25, 0x7c, 0x47, 0x46, 0x8e,
+	0x3a, 0xf0, 0x87, 0x89, 0x40, 0xb6, 0xf8, 0x9b, 0xd1, 0x5c, 0xf8, 0x2b, 0x2d, 0xe9, 0x57, 0xa4,
+	0x59, 0xef, 0xb2, 0xbb, 0x5e, 0x00, 0x47, 0xb6, 0x29, 0x30, 0xca, 0x67, 0x01, 0x69, 0x64, 0xf1,
+	0x82, 0xaf, 0xb5, 0xe8, 0x9f, 0xf8, 0x95, 0x63, 0xe6, 0xff, 0x00, 0x00, 0x00, 0xff, 0xff, 0xca,
+	0xa2, 0x76, 0x34, 0xe8, 0x08, 0x00, 0x00,
 }
diff --git a/jsonpb/jsonpb_test_proto/test_objects.proto b/jsonpb/jsonpb_test_proto/test_objects.proto
index ea4a048..911a9d5 100644
--- a/jsonpb/jsonpb_test_proto/test_objects.proto
+++ b/jsonpb/jsonpb_test_proto/test_objects.proto
@@ -31,6 +31,7 @@
 
 syntax = "proto2";
 
+import "google/protobuf/any.proto";
 import "google/protobuf/duration.proto";
 import "google/protobuf/struct.proto";
 import "google/protobuf/timestamp.proto";
@@ -116,6 +117,7 @@
 }
 
 message KnownTypes {
+  optional google.protobuf.Any an = 14;
   optional google.protobuf.Duration dur = 1;
   optional google.protobuf.Struct st = 12;
   optional google.protobuf.Timestamp ts = 2;