diff --git a/encoding/bench_test.go b/encoding/bench_test.go
index 5a541304..ab0fbbda 100644
--- a/encoding/bench_test.go
+++ b/encoding/bench_test.go
@@ -166,7 +166,7 @@ func BenchmarkTextDecode(b *testing.B) {
 		if *benchV1 {
 			err = protoV1.UnmarshalText(string(in), m)
 		} else {
-			err = prototext.Unmarshal(m, in)
+			err = prototext.Unmarshal(in, m)
 		}
 		if err != nil {
 			b.Fatal(err)
@@ -203,7 +203,7 @@ func BenchmarkJSONDecode(b *testing.B) {
 		if *benchV1 {
 			err = jsonpbV1.UnmarshalString(string(out), m)
 		} else {
-			err = protojson.Unmarshal(m, out)
+			err = protojson.Unmarshal(out, m)
 		}
 		if err != nil {
 			b.Fatal(err)
diff --git a/encoding/jsonpb/jsonpb.go b/encoding/jsonpb/jsonpb.go
index 43c28b5b..4cf24d67 100644
--- a/encoding/jsonpb/jsonpb.go
+++ b/encoding/jsonpb/jsonpb.go
@@ -1,13 +1,17 @@
 // Package jsonpb is deprecated.
 package jsonpb
 
-import "google.golang.org/protobuf/encoding/protojson"
-
-var (
-	Marshal   = protojson.Marshal
-	Unmarshal = protojson.Unmarshal
+import (
+	"google.golang.org/protobuf/encoding/protojson"
+	"google.golang.org/protobuf/proto"
 )
 
+var Marshal = protojson.Marshal
+
+func Unmarshal(m proto.Message, b []byte) error {
+	return protojson.Unmarshal(b, m)
+}
+
 type (
 	MarshalOptions   = protojson.MarshalOptions
 	UnmarshalOptions = protojson.UnmarshalOptions
diff --git a/encoding/protojson/bench_test.go b/encoding/protojson/bench_test.go
index 595c9089..70603afa 100644
--- a/encoding/protojson/bench_test.go
+++ b/encoding/protojson/bench_test.go
@@ -15,7 +15,7 @@ func BenchmarkUnmarshal_Duration(b *testing.B) {
 	input := []byte(`"-123456789.123456789s"`)
 
 	for i := 0; i < b.N; i++ {
-		err := protojson.Unmarshal(&knownpb.Duration{}, input)
+		err := protojson.Unmarshal(input, &knownpb.Duration{})
 		if err != nil {
 			b.Fatal(err)
 		}
diff --git a/encoding/protojson/decode.go b/encoding/protojson/decode.go
index b6c056ec..99e1a8b3 100644
--- a/encoding/protojson/decode.go
+++ b/encoding/protojson/decode.go
@@ -21,8 +21,8 @@ import (
 )
 
 // Unmarshal reads the given []byte into the given proto.Message.
-func Unmarshal(m proto.Message, b []byte) error {
-	return UnmarshalOptions{}.Unmarshal(m, b)
+func Unmarshal(b []byte, m proto.Message) error {
+	return UnmarshalOptions{}.Unmarshal(b, m)
 }
 
 // UnmarshalOptions is a configurable JSON format parser.
@@ -48,7 +48,7 @@ type UnmarshalOptions struct {
 // options in UnmarshalOptions object. It will clear the message first before
 // setting the fields. If it returns an error, the given message may be
 // partially set.
-func (o UnmarshalOptions) Unmarshal(m proto.Message, b []byte) error {
+func (o UnmarshalOptions) Unmarshal(b []byte, m proto.Message) error {
 	mr := m.ProtoReflect()
 	// TODO: Determine if we would like to have an option for merging or only
 	// have merging behavior.  We should at least be consistent with textproto
diff --git a/encoding/protojson/decode_test.go b/encoding/protojson/decode_test.go
index 75b28d31..ba8f10bc 100644
--- a/encoding/protojson/decode_test.go
+++ b/encoding/protojson/decode_test.go
@@ -2596,7 +2596,7 @@ func TestUnmarshal(t *testing.T) {
 	for _, tt := range tests {
 		tt := tt
 		t.Run(tt.desc, func(t *testing.T) {
-			err := tt.umo.Unmarshal(tt.inputMessage, []byte(tt.inputText))
+			err := tt.umo.Unmarshal([]byte(tt.inputText), tt.inputMessage)
 			if err != nil && !tt.wantErr {
 				t.Errorf("Unmarshal() returned error: %v\n\n", err)
 			}
diff --git a/encoding/prototext/decode.go b/encoding/prototext/decode.go
index f9263bdd..efc4c7af 100644
--- a/encoding/prototext/decode.go
+++ b/encoding/prototext/decode.go
@@ -20,8 +20,8 @@ import (
 )
 
 // Unmarshal reads the given []byte into the given proto.Message.
-func Unmarshal(m proto.Message, b []byte) error {
-	return UnmarshalOptions{}.Unmarshal(m, b)
+func Unmarshal(b []byte, m proto.Message) error {
+	return UnmarshalOptions{}.Unmarshal(b, m)
 }
 
 // UnmarshalOptions is a configurable textproto format unmarshaler.
@@ -41,7 +41,7 @@ type UnmarshalOptions struct {
 
 // Unmarshal reads the given []byte and populates the given proto.Message using options in
 // UnmarshalOptions object.
-func (o UnmarshalOptions) Unmarshal(m proto.Message, b []byte) error {
+func (o UnmarshalOptions) Unmarshal(b []byte, m proto.Message) error {
 	var nerr errors.NonFatal
 
 	mr := m.ProtoReflect()
diff --git a/encoding/prototext/decode_test.go b/encoding/prototext/decode_test.go
index 4837117b..20fcc947 100644
--- a/encoding/prototext/decode_test.go
+++ b/encoding/prototext/decode_test.go
@@ -1523,7 +1523,7 @@ type_url: "pb2.Nested"
 	for _, tt := range tests {
 		tt := tt
 		t.Run(tt.desc, func(t *testing.T) {
-			err := tt.umo.Unmarshal(tt.inputMessage, []byte(tt.inputText))
+			err := tt.umo.Unmarshal([]byte(tt.inputText), tt.inputMessage)
 			if err != nil && !tt.wantErr {
 				t.Errorf("Unmarshal() returned error: %v\n\n", err)
 			}
diff --git a/encoding/prototext/other_test.go b/encoding/prototext/other_test.go
index 4819f7d3..82620998 100644
--- a/encoding/prototext/other_test.go
+++ b/encoding/prototext/other_test.go
@@ -226,7 +226,7 @@ func TestRoundTrip(t *testing.T) {
 			}
 
 			gotMessage := new(pb2.KnownTypes)
-			err = prototext.UnmarshalOptions{Resolver: tt.resolver}.Unmarshal(gotMessage, b)
+			err = prototext.UnmarshalOptions{Resolver: tt.resolver}.Unmarshal(b, gotMessage)
 			if err != nil {
 				t.Errorf("Unmarshal() returned error: %v\n\n", err)
 			}
diff --git a/encoding/textpb/textpb.go b/encoding/textpb/textpb.go
index ba2c9ead..2c54d659 100644
--- a/encoding/textpb/textpb.go
+++ b/encoding/textpb/textpb.go
@@ -1,13 +1,17 @@
 // Package textpb is deprecated.
 package textpb
 
-import "google.golang.org/protobuf/encoding/prototext"
-
-var (
-	Marshal   = prototext.Marshal
-	Unmarshal = prototext.Unmarshal
+import (
+	"google.golang.org/protobuf/encoding/prototext"
+	"google.golang.org/protobuf/proto"
 )
 
+var Marshal = prototext.Marshal
+
+func Unmarshal(m proto.Message, b []byte) error {
+	return prototext.Unmarshal(b, m)
+}
+
 type (
 	MarshalOptions   = prototext.MarshalOptions
 	UnmarshalOptions = prototext.UnmarshalOptions
diff --git a/internal/cmd/conformance/main.go b/internal/cmd/conformance/main.go
index 52623761..ea54a828 100644
--- a/internal/cmd/conformance/main.go
+++ b/internal/cmd/conformance/main.go
@@ -71,7 +71,7 @@ func handle(req *pb.ConformanceRequest) *pb.ConformanceResponse {
 	case *pb.ConformanceRequest_JsonPayload:
 		err = protojson.UnmarshalOptions{
 			DiscardUnknown: req.TestCategory == pb.TestCategory_JSON_IGNORE_UNKNOWN_PARSING_TEST,
-		}.Unmarshal(msg, []byte(p.JsonPayload))
+		}.Unmarshal([]byte(p.JsonPayload), msg)
 	default:
 		return &pb.ConformanceResponse{
 			Result: &pb.ConformanceResponse_RuntimeError{