diff --git a/packages/connect/lib/connect.dart b/packages/connect/lib/connect.dart
index 19ef349..c028594 100644
--- a/packages/connect/lib/connect.dart
+++ b/packages/connect/lib/connect.dart
@@ -18,6 +18,7 @@ export 'src/abort.dart';
 export 'src/client.dart';
 export 'src/code.dart';
 export 'src/codec.dart';
+export 'src/compression.dart';
 export 'src/exception.dart';
 export 'src/headers.dart';
 export 'src/http.dart';
diff --git a/packages/connect/lib/io.dart b/packages/connect/lib/io.dart
index b1b954c..b7a9ee7 100644
--- a/packages/connect/lib/io.dart
+++ b/packages/connect/lib/io.dart
@@ -12,4 +12,5 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+export 'src/gzip.dart';
 export 'src/io.dart';
diff --git a/packages/connect/lib/src/compression.dart b/packages/connect/lib/src/compression.dart
new file mode 100644
index 0000000..a0a7d52
--- /dev/null
+++ b/packages/connect/lib/src/compression.dart
@@ -0,0 +1,22 @@
+// Copyright 2024 The Connect Authors
+//
+// 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.
+
+import 'dart:convert';
+import 'dart:typed_data';
+
+/// Compression is specialized [Codec] for a certain compression algorithm.
+abstract interface class Compression implements Codec<Uint8List, Uint8List> {
+  /// Name of the compression algorithm.
+  abstract final String name;
+}
diff --git a/packages/connect/lib/src/connect/header.dart b/packages/connect/lib/src/connect/header.dart
index c2ef820..a7a623e 100644
--- a/packages/connect/lib/src/connect/header.dart
+++ b/packages/connect/lib/src/connect/header.dart
@@ -14,6 +14,7 @@
 
 import '../abort.dart';
 import '../codec.dart';
+import '../compression.dart';
 import '../headers.dart';
 import '../spec.dart';
 import 'version.dart';
@@ -22,12 +23,18 @@ const headerContentType = "content-type";
 const headerContentLength = "content-length";
 const headerTimeout = "connect-timeout-ms";
 const headerProtocolVersion = "connect-protocol-version";
+const headerUnaryEncoding = "content-encoding";
+const headerStreamEncoding = "connect-content-encoding";
+const headerUnaryAcceptEncoding = "accept-encoding";
+const headerStreamAcceptEncoding = "connect-accept-encoding";
 
 Headers requestHeader(
   Codec codec,
   StreamType streamType,
   Headers? userProvidedHeaders,
   AbortSignal? signal,
+  Compression? sendCompression,
+  List<Compression> acceptCompressions,
 ) {
   final header = userProvidedHeaders == null
       ? Headers()
@@ -41,5 +48,16 @@ Headers requestHeader(
       ? 'application/${codec.name}'
       : 'application/connect+${codec.name}';
   // TODO: User agent headers.
+  if (sendCompression != null) {
+    header[streamType == StreamType.unary
+        ? headerUnaryEncoding
+        : headerStreamEncoding] = sendCompression.name;
+  }
+  if (acceptCompressions.isNotEmpty) {
+    header[streamType == StreamType.unary
+            ? headerUnaryAcceptEncoding
+            : headerStreamAcceptEncoding] =
+        acceptCompressions.map((c) => c.name).join(",");
+  }
   return header;
 }
diff --git a/packages/connect/lib/src/connect/protocol.dart b/packages/connect/lib/src/connect/protocol.dart
index 29345d3..d14cecc 100644
--- a/packages/connect/lib/src/connect/protocol.dart
+++ b/packages/connect/lib/src/connect/protocol.dart
@@ -14,6 +14,7 @@
 
 import '../code.dart';
 import '../codec.dart';
+import '../compression.dart';
 import '../exception.dart';
 import '../headers.dart';
 import '../http.dart';
@@ -42,6 +43,8 @@ final class Protocol implements base.Protocol {
   Headers requestHeaders<I, O>(
     Spec<I, O> spec,
     Codec codec,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
     CallOptions? options,
   ) {
     return requestHeader(
@@ -49,6 +52,8 @@ final class Protocol implements base.Protocol {
       spec.streamType,
       options?.headers,
       options?.signal,
+      sendCompression,
+      acceptCompressions,
     );
   }
 
@@ -57,6 +62,8 @@ final class Protocol implements base.Protocol {
     UnaryRequest<I, O> req,
     Codec codec,
     HttpClient httpClient,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
   ) async {
     final HttpRequest hReq;
     if (useHttpGet &&
@@ -73,20 +80,28 @@ final class Protocol implements base.Protocol {
         req.signal,
       );
     } else {
+      final body = codec.encode(req.message);
       hReq = HttpRequest(
         req.url,
         "POST",
         req.headers,
-        Stream.fromIterable([codec.encode(req.message)]),
+        Stream.fromIterable([sendCompression?.encode(body) ?? body]),
         req.signal,
       );
     }
     final res = await httpClient(hReq);
-    final unaryError = res.validate(req.spec.streamType, codec);
+    final (:compression, :unaryError) = res.validate(
+      req.spec.streamType,
+      codec,
+      acceptCompressions,
+    );
     final (:headers, :trailers) = res.header.demux();
-    final body = await res.body.toBytes(
+    var body = await res.body.toBytes(
       int.tryParse(headers[headerContentLength] ?? ''),
     );
+    if (compression != null) {
+      body = compression.decode(body);
+    }
     if (unaryError != null) {
       throw errorFromJsonBytes(
         body,
@@ -107,6 +122,8 @@ final class Protocol implements base.Protocol {
     StreamRequest<I, O> req,
     Codec codec,
     HttpClient httpClient,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
   ) async {
     final res = await httpClient(
       HttpRequest(
@@ -117,14 +134,15 @@ final class Protocol implements base.Protocol {
         req.signal,
       ),
     );
-    res.validate(req.spec.streamType, codec);
+    final (:compression, unaryError: _) =
+        res.validate(req.spec.streamType, codec, acceptCompressions);
     final trailer = Headers();
     return StreamResponse(
       req.spec,
       res.header,
       res.body
           .splitEnvelope()
-          .decompress()
+          .decompress(compression)
           .parse(
             codec,
             req.spec.outputFactory,
diff --git a/packages/connect/lib/src/connect/response.dart b/packages/connect/lib/src/connect/response.dart
index 4ad638f..d85e58c 100644
--- a/packages/connect/lib/src/connect/response.dart
+++ b/packages/connect/lib/src/connect/response.dart
@@ -14,9 +14,11 @@
 
 import '../code.dart';
 import '../codec.dart';
+import '../compression.dart';
 import '../exception.dart';
 import '../headers.dart';
 import '../http.dart';
+import '../protocol/compression.dart';
 import '../spec.dart';
 import 'header.dart';
 import 'http_status.dart';
@@ -28,10 +30,17 @@ extension ResponseValidation on HttpResponse {
   /// For unary RPCs with an HTTP error status, this returns an error
   /// derived from the HTTP status instead of throwing it, giving an
   /// implementation a chance to parse a Connect error from the wire.
-  ConnectException? validate(
+  ({ConnectException? unaryError, Compression? compression}) validate(
     StreamType streamType,
     Codec codec,
+    List<Compression> acceptCompressions,
   ) {
+    final compression = findCompression(
+      acceptCompressions,
+      streamType == StreamType.unary
+          ? headerUnaryEncoding
+          : headerStreamEncoding,
+    );
     final contentType = header[headerContentType] ?? '';
     if (status != 200) {
       final statusErr = ConnectException(
@@ -41,7 +50,7 @@ extension ResponseValidation on HttpResponse {
       if (streamType == StreamType.unary &&
           contentType.startsWith("application/json")) {
         // Unary JSON response
-        return statusErr;
+        return (unaryError: statusErr, compression: compression);
       }
       throw statusErr;
     }
@@ -58,6 +67,6 @@ extension ResponseValidation on HttpResponse {
         metadata: header,
       );
     }
-    return null;
+    return (unaryError: null, compression: compression);
   }
 }
diff --git a/packages/connect/lib/src/connect/transport.dart b/packages/connect/lib/src/connect/transport.dart
index a16d9a1..83468f1 100644
--- a/packages/connect/lib/src/connect/transport.dart
+++ b/packages/connect/lib/src/connect/transport.dart
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 import "../codec.dart";
+import "../compression.dart";
 import "../http.dart";
 import "../interceptor.dart";
 import "../protocol/transport.dart";
@@ -26,11 +27,15 @@ final class Transport extends ProtocolTransport {
     required HttpClient httpClient,
     List<Interceptor>? interceptors,
     bool useHttpGet = false,
+    Compression? sendCompression,
+    List<Compression>? acceptCompressions,
   }) : super(
           baseUrl,
           codec,
           Protocol(useHttpGet),
           httpClient,
           interceptors ?? [],
+          sendCompression,
+          acceptCompressions ?? [],
         );
 }
diff --git a/packages/connect/lib/src/fake.dart b/packages/connect/lib/src/fake.dart
index 58aa531..cc28d4f 100644
--- a/packages/connect/lib/src/fake.dart
+++ b/packages/connect/lib/src/fake.dart
@@ -17,6 +17,7 @@ import 'dart:typed_data';
 
 import 'abort.dart';
 import 'codec.dart';
+import 'compression.dart';
 import 'headers.dart';
 import 'http.dart';
 import 'interceptor.dart';
@@ -155,6 +156,8 @@ final class _FakeTransport extends ProtocolTransport {
           _FakeProtocol(handlers),
           (req) => throw UnimplementedError(),
           interceptors ?? [],
+          null,
+          [],
         );
 }
 
@@ -167,6 +170,8 @@ final class _FakeProtocol implements Protocol {
   Headers requestHeaders<I, O>(
     Spec<I, O> spec,
     Codec codec,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
     CallOptions? options,
   ) {
     final headers = Headers();
@@ -181,6 +186,8 @@ final class _FakeProtocol implements Protocol {
     UnaryRequest<I, O> req,
     Codec codec,
     HttpClient client,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
   ) async {
     final handler = handlers[req.spec];
     if (handler == null) {
@@ -211,6 +218,8 @@ final class _FakeProtocol implements Protocol {
     StreamRequest<I, O> req,
     Codec codec,
     HttpClient client,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
   ) async {
     final handler = handlers[req.spec];
     if (handler == null) {
diff --git a/packages/connect/lib/src/grpc/protocol.dart b/packages/connect/lib/src/grpc/protocol.dart
index 731ad87..2146527 100644
--- a/packages/connect/lib/src/grpc/protocol.dart
+++ b/packages/connect/lib/src/grpc/protocol.dart
@@ -14,6 +14,7 @@
 
 import '../code.dart';
 import '../codec.dart';
+import '../compression.dart';
 import '../exception.dart';
 import '../headers.dart';
 import '../http.dart';
@@ -32,16 +33,25 @@ import 'trailer.dart';
 
 final class Protocol implements base.Protocol {
   final StatusParser statusParser;
+  final Compression? sendCompression;
 
-  const Protocol(this.statusParser);
+  const Protocol(this.statusParser, this.sendCompression);
 
   @override
   Headers requestHeaders<I, O>(
     Spec<I, O> spec,
     Codec codec,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
     CallOptions? options,
   ) {
-    return requestHeader(codec, options?.headers, options?.signal);
+    return requestHeader(
+      codec,
+      options?.headers,
+      options?.signal,
+      sendCompression,
+      acceptCompressions,
+    );
   }
 
   @override
@@ -49,20 +59,28 @@ final class Protocol implements base.Protocol {
     UnaryRequest<I, O> req,
     Codec codec,
     HttpClient httpClient,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
   ) async {
     final res = await httpClient(
       HttpRequest(
         req.url,
         "POST",
         req.headers,
-        Stream.fromIterable([encodeEnvelope(0, codec.encode(req.message))]),
+        Stream.fromIterable([req.message])
+            .serialize(codec)
+            .compress(sendCompression)
+            .joinEnvelope(),
         req.signal,
       ),
     );
-    final (foundStatus: _, :headerError) = res.validate(statusParser);
+    final (foundStatus: _, :headerError, :compression) = res.validate(
+      statusParser,
+      acceptCompressions,
+    );
     final message = await res.body
         .splitEnvelope()
-        .decompress()
+        .decompress(compression)
         .parse(codec, req.spec.outputFactory)
         .tryReadingSingleMessage();
     res.trailer.validateTrailer(res.header, statusParser);
@@ -98,17 +116,22 @@ final class Protocol implements base.Protocol {
     StreamRequest<I, O> req,
     Codec codec,
     HttpClient httpClient,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
   ) async {
     final res = await httpClient(
       HttpRequest(
         req.url,
         "POST",
         req.headers,
-        req.message.serialize(codec).joinEnvelope(),
+        req.message.serialize(codec).compress(sendCompression).joinEnvelope(),
         req.signal,
       ),
     );
-    final (:foundStatus, :headerError) = res.validate(statusParser);
+    final (:foundStatus, :headerError, :compression) = res.validate(
+      statusParser,
+      acceptCompressions,
+    );
     if (headerError != null) {
       // Trailers only response.
       throw headerError;
@@ -118,7 +141,7 @@ final class Protocol implements base.Protocol {
       res.header,
       res.body
           .splitEnvelope()
-          .decompress()
+          .decompress(compression)
           .parse(codec, req.spec.outputFactory)
           .onDone(() {
         if (!foundStatus) {
diff --git a/packages/connect/lib/src/grpc/request_header.dart b/packages/connect/lib/src/grpc/request_header.dart
index 7f75c80..103f9d0 100644
--- a/packages/connect/lib/src/grpc/request_header.dart
+++ b/packages/connect/lib/src/grpc/request_header.dart
@@ -14,6 +14,7 @@
 
 import '../abort.dart';
 import '../codec.dart';
+import '../compression.dart';
 import '../headers.dart';
 import 'headers.dart';
 
@@ -23,6 +24,8 @@ Headers requestHeader(
   Codec codec,
   Headers? userProvidedHeaders,
   AbortSignal? signal,
+  Compression? sendCompression,
+  List<Compression> acceptCompressions,
 ) {
   final header = userProvidedHeaders == null
       ? Headers()
@@ -36,5 +39,12 @@ Headers requestHeader(
   // don't support HTTP trailers.
   header["Te"] = "trailers";
   // TODO: User agent headers.
+  if (sendCompression != null) {
+    header[headerEncoding] = sendCompression.name;
+  }
+  if (acceptCompressions.isNotEmpty) {
+    header[headerAcceptEncoding] =
+        acceptCompressions.map((c) => c.name).join(",");
+  }
   return header;
 }
diff --git a/packages/connect/lib/src/grpc/response.dart b/packages/connect/lib/src/grpc/response.dart
index 1bd5726..1489902 100644
--- a/packages/connect/lib/src/grpc/response.dart
+++ b/packages/connect/lib/src/grpc/response.dart
@@ -12,15 +12,16 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import 'package:connectrpc/src/grpc/request_header.dart';
-
 import '../code.dart';
+import '../compression.dart';
 import '../exception.dart';
-import '../grpc/headers.dart';
-import '../grpc/status.dart';
-import '../grpc/trailer_error.dart';
 import '../headers.dart';
 import '../http.dart';
+import '../protocol/compression.dart';
+import './headers.dart';
+import './request_header.dart';
+import './status.dart';
+import './trailer_error.dart';
 import 'http_status.dart';
 
 extension ResponseValidation on HttpResponse {
@@ -32,8 +33,13 @@ extension ResponseValidation on HttpResponse {
   /// Returns an object that indicates whether a gRPC status was found
   /// in the response header. In this case, clients can not expect a
   /// trailer.
-  ({bool foundStatus, ConnectException? headerError}) validate(
+  ({
+    bool foundStatus,
+    ConnectException? headerError,
+    Compression? compression,
+  }) validate(
     StatusParser statusParser,
+    List<Compression> acceptCompressions,
   ) {
     if (status != 200) {
       throw ConnectException(
@@ -42,14 +48,6 @@ extension ResponseValidation on HttpResponse {
         metadata: header,
       );
     }
-    final encoding = header[headerEncoding];
-    if (encoding != null && header[headerEncoding] != "identity") {
-      throw ConnectException(
-        Code.internal,
-        'unsupported response encoding "$encoding"',
-        metadata: header,
-      );
-    }
     final contentType = header[headerContentType] ?? '';
     if (!contentType.startsWith(contentTypePrefix)) {
       throw ConnectException(
@@ -60,7 +58,8 @@ extension ResponseValidation on HttpResponse {
     }
     return (
       foundStatus: header.contains(headerGrpcStatus),
-      headerError: header.findError(statusParser)
+      headerError: header.findError(statusParser),
+      compression: findCompression(acceptCompressions, headerEncoding)
     );
   }
 }
diff --git a/packages/connect/lib/src/grpc/transport.dart b/packages/connect/lib/src/grpc/transport.dart
index 05b4e2d..a3434cb 100644
--- a/packages/connect/lib/src/grpc/transport.dart
+++ b/packages/connect/lib/src/grpc/transport.dart
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 import '../codec.dart';
+import '../compression.dart';
 import '../http.dart';
 import '../interceptor.dart';
 import '../protocol/transport.dart';
@@ -30,11 +31,15 @@ final class Transport extends ProtocolTransport {
     required HttpClient httpClient,
     required StatusParser statusParser,
     List<Interceptor>? interceptors,
+    Compression? sendCompression,
+    List<Compression>? acceptCompressions,
   }) : super(
           baseUrl,
           codec,
-          Protocol(statusParser),
+          Protocol(statusParser, sendCompression),
           httpClient,
           interceptors ?? [],
+          sendCompression,
+          acceptCompressions ?? [],
         );
 }
diff --git a/packages/connect/lib/src/grpc_web/protocol.dart b/packages/connect/lib/src/grpc_web/protocol.dart
index 81617a4..69d4525 100644
--- a/packages/connect/lib/src/grpc_web/protocol.dart
+++ b/packages/connect/lib/src/grpc_web/protocol.dart
@@ -16,6 +16,7 @@ import 'dart:async';
 
 import '../code.dart';
 import '../codec.dart';
+import '../compression.dart';
 import '../exception.dart';
 import '../grpc/headers.dart';
 import '../grpc/status.dart';
@@ -42,9 +43,17 @@ final class Protocol implements base.Protocol {
   Headers requestHeaders<I, O>(
     Spec<I, O> spec,
     Codec codec,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
     CallOptions? options,
   ) {
-    return requestHeader(codec, options?.headers, options?.signal);
+    return requestHeader(
+      codec,
+      options?.headers,
+      options?.signal,
+      sendCompression,
+      acceptCompressions,
+    );
   }
 
   @override
@@ -52,20 +61,28 @@ final class Protocol implements base.Protocol {
     UnaryRequest<I, O> req,
     Codec codec,
     HttpClient httpClient,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
   ) async {
     final res = await httpClient(
       HttpRequest(
         req.url,
         "POST",
         req.headers,
-        Stream.fromIterable([encodeEnvelope(0, codec.encode(req.message))]),
+        Stream.fromIterable([req.message])
+            .serialize(codec)
+            .compress(sendCompression)
+            .joinEnvelope(),
         req.signal,
       ),
     );
-    final (:foundStatus, :headerError) = res.validate(statusParser);
+    final (:foundStatus, :headerError, :compression) = res.validate(
+      statusParser,
+      acceptCompressions,
+    );
     final (message, trailer) = await res.body
         .splitEnvelope()
-        .decompress()
+        .decompress(compression)
         .parse(
           codec,
           req.spec.outputFactory,
@@ -102,6 +119,8 @@ final class Protocol implements base.Protocol {
     StreamRequest<I, O> req,
     Codec codec,
     HttpClient httpClient,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
   ) async {
     final res = await httpClient(
       HttpRequest(
@@ -112,7 +131,10 @@ final class Protocol implements base.Protocol {
         req.signal,
       ),
     );
-    final (:foundStatus, :headerError) = res.validate(statusParser);
+    final (:foundStatus, :headerError, :compression) = res.validate(
+      statusParser,
+      acceptCompressions,
+    );
     if (headerError != null) {
       throw headerError;
     }
@@ -122,7 +144,7 @@ final class Protocol implements base.Protocol {
       res.header,
       res.body
           .splitEnvelope()
-          .decompress()
+          .decompress(compression)
           .parse(
             codec,
             req.spec.outputFactory,
diff --git a/packages/connect/lib/src/grpc_web/request_header.dart b/packages/connect/lib/src/grpc_web/request_header.dart
index 1a943d0..2331c31 100644
--- a/packages/connect/lib/src/grpc_web/request_header.dart
+++ b/packages/connect/lib/src/grpc_web/request_header.dart
@@ -14,6 +14,7 @@
 
 import '../abort.dart';
 import '../codec.dart';
+import '../compression.dart';
 import '../grpc/headers.dart';
 import '../headers.dart';
 
@@ -30,6 +31,8 @@ Headers requestHeader(
   Codec codec,
   Headers? userProvidedHeaders,
   AbortSignal? signal,
+  Compression? sendCompression,
+  List<Compression> acceptCompressions,
 ) {
   final header = userProvidedHeaders == null
       ? Headers()
@@ -43,5 +46,12 @@ Headers requestHeader(
         '${deadline.difference(DateTime.now()).inMilliseconds}m';
   }
   // TODO: User agent headers.
+  if (sendCompression != null) {
+    header[headerEncoding] = sendCompression.name;
+  }
+  if (acceptCompressions.isNotEmpty) {
+    header[headerAcceptEncoding] =
+        acceptCompressions.map((c) => c.name).join(",");
+  }
   return header;
 }
diff --git a/packages/connect/lib/src/grpc_web/response.dart b/packages/connect/lib/src/grpc_web/response.dart
index 13815cc..46b755e 100644
--- a/packages/connect/lib/src/grpc_web/response.dart
+++ b/packages/connect/lib/src/grpc_web/response.dart
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import '../code.dart';
+import '../compression.dart';
 import '../exception.dart';
 import '../grpc/headers.dart';
 import '../grpc/http_status.dart';
@@ -20,6 +20,7 @@ import '../grpc/status.dart';
 import '../grpc/trailer_error.dart';
 import '../headers.dart';
 import '../http.dart';
+import '../protocol/compression.dart';
 
 extension ResponseValidation on HttpResponse {
   /// Validates response status and header for the gRPC-web protocol.
@@ -30,23 +31,21 @@ extension ResponseValidation on HttpResponse {
   /// Returns an object that indicates whether a gRPC status was found
   /// in the response header. In this case, clients can not expect a
   /// trailer.
-  ({bool foundStatus, ConnectException? headerError}) validate(
+  ({
+    bool foundStatus,
+    ConnectException? headerError,
+    Compression? compression,
+  }) validate(
     StatusParser statusParser,
+    List<Compression> acceptCompression,
   ) {
-    final encoding = header[headerEncoding];
-    if (encoding != null && header[headerEncoding] != "identity") {
-      throw ConnectException(
-        Code.internal,
-        'unsupported response encoding "$encoding"',
-        metadata: header,
-      );
-    }
     // For compatibility with the `grpc-web` package, we treat all HTTP status
     // codes in the 200 range as valid, not just HTTP 200.
     if (status >= 200 && status < 300) {
       return (
         foundStatus: header.contains(headerGrpcStatus),
-        headerError: header.findError(statusParser)
+        headerError: header.findError(statusParser),
+        compression: findCompression(acceptCompression, headerEncoding),
       );
     }
     throw ConnectException(
diff --git a/packages/connect/lib/src/grpc_web/transport.dart b/packages/connect/lib/src/grpc_web/transport.dart
index 11b1533..5f093fa 100644
--- a/packages/connect/lib/src/grpc_web/transport.dart
+++ b/packages/connect/lib/src/grpc_web/transport.dart
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 import "../codec.dart";
+import "../compression.dart";
 import "../grpc/status.dart";
 import "../http.dart";
 import "../interceptor.dart";
@@ -27,11 +28,15 @@ final class Transport extends ProtocolTransport {
     required HttpClient httpClient,
     required StatusParser statusParser,
     List<Interceptor>? interceptors,
+    Compression? sendCompression,
+    List<Compression>? acceptCompressions,
   }) : super(
           baseUrl,
           codec,
           Protocol(statusParser),
           httpClient,
           interceptors ?? [],
+          sendCompression,
+          acceptCompressions ?? [],
         );
 }
diff --git a/packages/connect/lib/src/gzip.dart b/packages/connect/lib/src/gzip.dart
new file mode 100644
index 0000000..1beeabb
--- /dev/null
+++ b/packages/connect/lib/src/gzip.dart
@@ -0,0 +1,46 @@
+// Copyright 2024 The Connect Authors
+//
+// 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.
+
+import 'dart:convert';
+import 'dart:io';
+import 'dart:typed_data';
+
+import 'compression.dart';
+
+/// [Compression] that supports gzip compression algorithm.
+final class GzipCompression extends Codec<Uint8List, Uint8List>
+    implements Compression {
+  final GZipCodec _codec;
+  late final _Converter _encoder = _Converter(_codec.encoder);
+  late final _Converter _decoder = _Converter(_codec.decoder);
+
+  GzipCompression({GZipCodec? codec}) : _codec = codec ?? gzip;
+  @override
+  String get name => "gzip";
+
+  @override
+  Converter<Uint8List, Uint8List> get decoder => _decoder;
+
+  @override
+  Converter<Uint8List, Uint8List> get encoder => _encoder;
+}
+
+final class _Converter extends Converter<Uint8List, Uint8List> {
+  final Converter<List<int>, List<int>> converter;
+  const _Converter(this.converter);
+  @override
+  Uint8List convert(Uint8List input) {
+    return Uint8List.fromList(converter.convert(input));
+  }
+}
diff --git a/packages/connect/lib/src/io.dart b/packages/connect/lib/src/io.dart
index b0fc6de..73abaae 100644
--- a/packages/connect/lib/src/io.dart
+++ b/packages/connect/lib/src/io.dart
@@ -28,8 +28,10 @@ import 'sentinel.dart';
 HttpClient createHttpClient(io.HttpClient client) {
   return (creq) async {
     final req = await client.openUrl(creq.method, Uri.parse(creq.url));
-    // Remove default values.
-    req.headers.removeAll("accept-encoding");
+    // We don't want compression unless it came from upstream.
+    //
+    // Ref: https://api.dart.dev/dart-io/HttpClient-class.html
+    req.headers.removeAll(io.HttpHeaders.acceptEncodingHeader);
     for (final header in creq.header.entries) {
       req.headers.add(header.name, header.value);
     }
@@ -44,8 +46,19 @@ HttpClient createHttpClient(io.HttpClient client) {
       }
     }
     final res = await sentinel.race(req.close());
+    final compressed =
+        res.headers.value(io.HttpHeaders.contentEncodingHeader) == 'gzip';
     final headers = Headers();
     res.headers.forEach((key, values) {
+      // It automatically decompresses gzip responses, but keeps the
+      // original content-length and accept-encoding headers.
+      //
+      // Ref: https://api.dart.dev/dart-io/HttpClient-class.html
+      if (compressed &&
+          (key == io.HttpHeaders.contentLengthHeader ||
+              key == io.HttpHeaders.contentEncodingHeader)) {
+        return;
+      }
       for (final value in values) {
         headers.add(key, value);
       }
diff --git a/packages/connect/lib/src/protocol/compression.dart b/packages/connect/lib/src/protocol/compression.dart
index 719f81b..8118cb7 100644
--- a/packages/connect/lib/src/protocol/compression.dart
+++ b/packages/connect/lib/src/protocol/compression.dart
@@ -15,7 +15,10 @@
 import 'dart:async';
 
 import '../code.dart';
+import '../compression.dart';
 import '../exception.dart';
+import '../headers.dart';
+import '../http.dart';
 import 'envelope.dart';
 
 /// Indicates that the data in a EnvelopedMessage is
@@ -24,17 +27,63 @@ import 'envelope.dart';
 ///
 const compressedFlag = 1; // 0b00000001
 
-extension DecompressEnvelope on Stream<EnvelopedMessage> {
-  /// Noop for now. Just ensures everything is uncompressed.
-  Stream<EnvelopedMessage> decompress() async* {
+extension EnvelopeStreamCompression on Stream<EnvelopedMessage> {
+  /// Decompressess the envoloped messaged if the [compression] is not null and
+  /// the envelope is compressed.
+  Stream<EnvelopedMessage> decompress(
+    Compression? compression,
+  ) async* {
     await for (final env in this) {
-      if ((env.flags & compressedFlag) == compressedFlag) {
+      if (env.flags & compressedFlag == compressedFlag) {
+        if (compression == null) {
+          throw ConnectException(
+            Code.internal,
+            "received compressed envelope, but do not know how to decompress",
+          );
+        }
+        yield EnvelopedMessage(
+          env.flags ^ compressedFlag,
+          compression.decode(env.data),
+        );
+      } else {
+        yield env;
+      }
+    }
+  }
+
+  /// Compresses an uncompressed enveloped message using the given
+  /// [compression].
+  Stream<EnvelopedMessage> compress(
+    Compression? compression,
+  ) {
+    if (compression == null) {
+      return this;
+    }
+    return (() async* {
+      await for (final env in this) {
+        yield EnvelopedMessage(
+          env.flags | compressedFlag,
+          compression.encode(env.data),
+        );
+      }
+    })();
+  }
+}
+
+extension FindCompression on HttpResponse {
+  Compression? findCompression(List<Compression> accept, String headerKey) {
+    final encoding = header[headerKey];
+    if (encoding != null && encoding.toLowerCase() != 'identity') {
+      final i = accept.indexWhere((c) => c.name == encoding);
+      if (i < 0) {
         throw ConnectException(
           Code.internal,
-          "received compressed envelope, but do not know how to decompress",
+          'unsupported response encoding "$encoding"',
+          metadata: header,
         );
       }
-      yield env;
+      return accept[i];
     }
+    return null;
   }
 }
diff --git a/packages/connect/lib/src/protocol/protocol.dart b/packages/connect/lib/src/protocol/protocol.dart
index 78733ef..c287d59 100644
--- a/packages/connect/lib/src/protocol/protocol.dart
+++ b/packages/connect/lib/src/protocol/protocol.dart
@@ -12,7 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import 'package:connectrpc/connect.dart';
+import '../codec.dart';
+import '../compression.dart';
+import '../headers.dart';
+import '../http.dart';
+import '../interceptor.dart';
+import '../spec.dart';
+import '../transport.dart';
 
 /// Protocol is common abstraction of an RPC protocol over HTTP.
 abstract interface class Protocol {
@@ -20,6 +26,8 @@ abstract interface class Protocol {
   Headers requestHeaders<I, O>(
     Spec<I, O> spec,
     Codec codec,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
     CallOptions? options,
   );
 
@@ -29,6 +37,8 @@ abstract interface class Protocol {
     UnaryRequest<I, O> req,
     Codec codec,
     HttpClient client,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
   );
 
   /// Performs a stream request using the given [client] according
@@ -37,5 +47,7 @@ abstract interface class Protocol {
     StreamRequest<I, O> req,
     Codec codec,
     HttpClient client,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
   );
 }
diff --git a/packages/connect/lib/src/protocol/transport.dart b/packages/connect/lib/src/protocol/transport.dart
index d590ecb..4714d88 100644
--- a/packages/connect/lib/src/protocol/transport.dart
+++ b/packages/connect/lib/src/protocol/transport.dart
@@ -14,6 +14,7 @@
 
 import '../abort.dart';
 import '../codec.dart';
+import '../compression.dart';
 import '../http.dart';
 import '../interceptor.dart';
 import '../spec.dart';
@@ -28,6 +29,8 @@ abstract base class ProtocolTransport implements Transport {
   final Protocol _protocol;
   final HttpClient _httpClient;
   final List<Interceptor> _interceptors;
+  final Compression? sendCompression;
+  final List<Compression> acceptCompressions;
 
   ProtocolTransport(
     String baseUrl,
@@ -35,6 +38,8 @@ abstract base class ProtocolTransport implements Transport {
     this._protocol,
     this._httpClient,
     this._interceptors,
+    this.sendCompression,
+    this.acceptCompressions,
   ) : _baseUrl = baseUrl.replaceAll(RegExp(r'/?$'), "");
 
   @override
@@ -48,12 +53,24 @@ abstract base class ProtocolTransport implements Transport {
       final req = UnaryRequest(
         spec,
         _baseUrl + spec.procedure,
-        _protocol.requestHeaders(spec, _codec, options),
+        _protocol.requestHeaders(
+          spec,
+          _codec,
+          sendCompression,
+          acceptCompressions,
+          options,
+        ),
         input,
         signal,
       );
       if (_interceptors.isEmpty) {
-        return await _protocol.unary(req, _codec, _httpClient);
+        return await _protocol.unary(
+          req,
+          _codec,
+          _httpClient,
+          sendCompression,
+          acceptCompressions,
+        );
       }
       final first = _interceptors.apply<I, O>(
         (req) async {
@@ -61,6 +78,8 @@ abstract base class ProtocolTransport implements Transport {
             req as UnaryRequest<I, O>,
             _codec,
             _httpClient,
+            sendCompression,
+            acceptCompressions,
           );
         },
       );
@@ -82,13 +101,25 @@ abstract base class ProtocolTransport implements Transport {
       final req = StreamRequest(
         spec,
         _baseUrl + spec.procedure,
-        _protocol.requestHeaders(spec, _codec, options),
+        _protocol.requestHeaders(
+          spec,
+          _codec,
+          sendCompression,
+          acceptCompressions,
+          options,
+        ),
         input,
         signal,
       );
       late final StreamResponse<I, O> res;
       if (_interceptors.isEmpty) {
-        res = await _protocol.stream(req, _codec, _httpClient);
+        res = await _protocol.stream(
+          req,
+          _codec,
+          _httpClient,
+          sendCompression,
+          acceptCompressions,
+        );
       } else {
         final first = _interceptors.apply<I, O>(
           (req) async {
@@ -96,6 +127,8 @@ abstract base class ProtocolTransport implements Transport {
               req as StreamRequest<I, O>,
               _codec,
               _httpClient,
+              sendCompression,
+              acceptCompressions,
             );
           },
         );
diff --git a/packages/connect/test/conformance/conformance.io.yaml b/packages/connect/test/conformance/conformance.io.yaml
index f066cfc..6377aaf 100644
--- a/packages/connect/test/conformance/conformance.io.yaml
+++ b/packages/connect/test/conformance/conformance.io.yaml
@@ -11,6 +11,7 @@ features:
     - CODEC_JSON
   compressions:
     - COMPRESSION_IDENTITY
+    - COMPRESSION_GZIP
   supportsTls: true
   supportsH2c: false
   supportsTlsClientCerts: true
diff --git a/packages/connect/test/conformance/io_test.dart b/packages/connect/test/conformance/io_test.dart
index 257cf77..13c2235 100644
--- a/packages/connect/test/conformance/io_test.dart
+++ b/packages/connect/test/conformance/io_test.dart
@@ -25,6 +25,7 @@ import 'package:connectrpc/protobuf.dart';
 import 'package:connectrpc/protocol/connect.dart' as connect;
 import 'package:connectrpc/protocol/grpc.dart' as grpc;
 import 'package:connectrpc/protocol/grpc_web.dart' as grpc_web;
+import 'package:connectrpc/src/gzip.dart';
 import 'package:protobuf/protobuf.dart';
 import 'package:test/test.dart';
 
@@ -69,24 +70,36 @@ void main() {
         HTTPVersion.HTTP_VERSION_2 => http2.createHttpClient(context: context),
         _ => throw 'Unsupported Http version',
       };
+      final compression = switch (req.compression) {
+        Compression.COMPRESSION_GZIP => GzipCompression(),
+        Compression.COMPRESSION_UNSPECIFIED => null,
+        Compression.COMPRESSION_IDENTITY => null,
+        _ => throw 'Unsupported compression ${req.compression.name}',
+      };
       return switch (req.protocol) {
         Protocol.PROTOCOL_CONNECT => connect.Transport(
             baseUrl: baseUrl,
             codec: codec,
             httpClient: httpClient,
             useHttpGet: req.useGetHttpMethod,
+            sendCompression: compression,
+            acceptCompressions: compression != null ? [compression] : [],
           ),
         Protocol.PROTOCOL_GRPC => grpc.Transport(
             baseUrl: baseUrl,
             codec: codec,
             httpClient: httpClient,
             statusParser: StatusParser(),
+            sendCompression: compression,
+            acceptCompressions: compression != null ? [compression] : [],
           ),
         Protocol.PROTOCOL_GRPC_WEB => grpc_web.Transport(
             baseUrl: baseUrl,
             codec: codec,
             httpClient: httpClient,
             statusParser: StatusParser(),
+            sendCompression: compression,
+            acceptCompressions: compression != null ? [compression] : [],
           ),
         _ => throw "Unknown protocol",
       };
diff --git a/packages/connect/test/protocol/transport_test.dart b/packages/connect/test/protocol/transport_test.dart
index b59c99e..6354b6d 100644
--- a/packages/connect/test/protocol/transport_test.dart
+++ b/packages/connect/test/protocol/transport_test.dart
@@ -196,6 +196,8 @@ class DelegatingProtocol implements Protocol {
   Headers requestHeaders<I, O>(
     Spec<I, O> spec,
     Codec codec,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
     CallOptions? options,
   ) {
     final onRequestHeaders = this.onRequestHeaders;
@@ -214,6 +216,8 @@ class DelegatingProtocol implements Protocol {
     UnaryRequest<I, O> req,
     Codec codec,
     HttpClient client,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
   ) async {
     final onUnary = this.onUnary;
     if (onUnary != null) {
@@ -233,6 +237,8 @@ class DelegatingProtocol implements Protocol {
     StreamRequest<I, O> req,
     Codec codec,
     HttpClient client,
+    Compression? sendCompression,
+    List<Compression> acceptCompressions,
   ) async {
     final onStream = this.onStream;
     if (onStream != null) {
@@ -258,6 +264,8 @@ final class TestTransport extends ProtocolTransport {
           protocol,
           (req) => throw UnimplementedError(),
           interceptors ?? [],
+          null,
+          [],
         );
 }