diff --git a/okhttp/src/main/java/com/squareup/okhttp/Address.java b/okhttp/src/main/java/com/squareup/okhttp/Address.java
index a787a94a6..b34bd9128 100644
--- a/okhttp/src/main/java/com/squareup/okhttp/Address.java
+++ b/okhttp/src/main/java/com/squareup/okhttp/Address.java
@@ -15,8 +15,10 @@
  */
 package com.squareup.okhttp;
 
+import com.squareup.okhttp.internal.Util;
 import java.net.Proxy;
 import java.net.UnknownHostException;
+import java.util.List;
 import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.SSLSocketFactory;
 
@@ -39,19 +41,22 @@ public final class Address {
   final SSLSocketFactory sslSocketFactory;
   final HostnameVerifier hostnameVerifier;
   final OkAuthenticator authenticator;
+  final List<String> transports;
 
   public Address(String uriHost, int uriPort, SSLSocketFactory sslSocketFactory,
-      HostnameVerifier hostnameVerifier, OkAuthenticator authenticator, Proxy proxy)
-      throws UnknownHostException {
+      HostnameVerifier hostnameVerifier, OkAuthenticator authenticator, Proxy proxy,
+      List<String> transports) throws UnknownHostException {
     if (uriHost == null) throw new NullPointerException("uriHost == null");
     if (uriPort <= 0) throw new IllegalArgumentException("uriPort <= 0: " + uriPort);
     if (authenticator == null) throw new IllegalArgumentException("authenticator == null");
+    if (transports == null) throw new IllegalArgumentException("transports == null");
     this.proxy = proxy;
     this.uriHost = uriHost;
     this.uriPort = uriPort;
     this.sslSocketFactory = sslSocketFactory;
     this.hostnameVerifier = hostnameVerifier;
     this.authenticator = authenticator;
+    this.transports = Util.immutableList(transports);
   }
 
   /** Returns the hostname of the origin server. */
@@ -91,6 +96,14 @@ public final class Address {
     return authenticator;
   }
 
+  /**
+   * Returns the client's transports. This method always returns a non-null list
+   * that contains "http/1.1", possibly among other transports.
+   */
+  public List<String> getTransports() {
+    return transports;
+  }
+
   /**
    * Returns this address's explicitly-specified HTTP proxy, or null to
    * delegate to the HTTP client's proxy selector.
@@ -107,7 +120,8 @@ public final class Address {
           && this.uriPort == that.uriPort
           && equal(this.sslSocketFactory, that.sslSocketFactory)
           && equal(this.hostnameVerifier, that.hostnameVerifier)
-          && equal(this.authenticator, that.authenticator);
+          && equal(this.authenticator, that.authenticator)
+          && equal(this.transports, that.transports);
     }
     return false;
   }
@@ -120,6 +134,7 @@ public final class Address {
     result = 31 * result + (hostnameVerifier != null ? hostnameVerifier.hashCode() : 0);
     result = 31 * result + (authenticator != null ? authenticator.hashCode() : 0);
     result = 31 * result + (proxy != null ? proxy.hashCode() : 0);
+    result = 31 * result + transports.hashCode();
     return result;
   }
 }
diff --git a/okhttp/src/main/java/com/squareup/okhttp/Connection.java b/okhttp/src/main/java/com/squareup/okhttp/Connection.java
index e9ccb9806..ce94a9fa9 100644
--- a/okhttp/src/main/java/com/squareup/okhttp/Connection.java
+++ b/okhttp/src/main/java/com/squareup/okhttp/Connection.java
@@ -134,7 +134,8 @@ public final class Connection implements Closeable {
       platform.supportTlsIntolerantServer(sslSocket);
     }
 
-    if (route.modernTls) {
+    boolean useNpn = route.modernTls && route.address.transports.contains("spdy/3");
+    if (useNpn) {
       platform.setNpnProtocols(sslSocket, NPN_PROTOCOLS);
     }
 
@@ -150,8 +151,7 @@ public final class Connection implements Closeable {
     in = sslSocket.getInputStream();
 
     byte[] selectedProtocol;
-    if (route.modernTls
-        && (selectedProtocol = platform.getNpnSelectedProtocol(sslSocket)) != null) {
+    if (useNpn && (selectedProtocol = platform.getNpnSelectedProtocol(sslSocket)) != null) {
       if (Arrays.equals(selectedProtocol, SPDY3)) {
         sslSocket.setSoTimeout(0); // SPDY timeouts are set per-stream.
         spdyConnection = new SpdyConnection.Builder(route.address.getUriHost(), true, in, out)
diff --git a/okhttp/src/main/java/com/squareup/okhttp/OkHttpClient.java b/okhttp/src/main/java/com/squareup/okhttp/OkHttpClient.java
index 41c65e195..faddbc1f3 100644
--- a/okhttp/src/main/java/com/squareup/okhttp/OkHttpClient.java
+++ b/okhttp/src/main/java/com/squareup/okhttp/OkHttpClient.java
@@ -15,6 +15,7 @@
  */
 package com.squareup.okhttp;
 
+import com.squareup.okhttp.internal.Util;
 import com.squareup.okhttp.internal.http.HttpAuthenticator;
 import com.squareup.okhttp.internal.http.HttpURLConnectionImpl;
 import com.squareup.okhttp.internal.http.HttpsURLConnectionImpl;
@@ -27,8 +28,10 @@ import java.net.Proxy;
 import java.net.ProxySelector;
 import java.net.ResponseCache;
 import java.net.URL;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Set;
 import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.HttpsURLConnection;
@@ -36,8 +39,12 @@ import javax.net.ssl.SSLSocketFactory;
 
 /** Configures and creates HTTP connections. */
 public final class OkHttpClient {
+  private static final List<String> DEFAULT_TRANSPORTS
+      = Util.immutableList(Arrays.asList("spdy/3", "http/1.1"));
+
   private Proxy proxy;
-  private Set<Route> failedRoutes = Collections.synchronizedSet(new LinkedHashSet<Route>());
+  private List<String> transports;
+  private final Set<Route> failedRoutes;
   private ProxySelector proxySelector;
   private CookieHandler cookieHandler;
   private ResponseCache responseCache;
@@ -47,6 +54,14 @@ public final class OkHttpClient {
   private ConnectionPool connectionPool;
   private boolean followProtocolRedirects = true;
 
+  public OkHttpClient() {
+    this.failedRoutes = Collections.synchronizedSet(new LinkedHashSet<Route>());
+  }
+
+  private OkHttpClient(OkHttpClient copyFrom) {
+    this.failedRoutes = copyFrom.failedRoutes; // Avoid allocating an unnecessary LinkedHashSet.
+  }
+
   /**
    * Sets the HTTP proxy that will be used by connections created by this
    * client. This takes precedence over {@link #setProxySelector}, which is
@@ -199,6 +214,49 @@ public final class OkHttpClient {
     return followProtocolRedirects;
   }
 
+  /**
+   * Configure the transports used by this client to communicate with remote
+   * servers. By default this client will prefer the most efficient transport
+   * available, falling back to more ubiquitous transports. Applications should
+   * only call this method to avoid specific compatibility problems, such as web
+   * servers that behave incorrectly when SPDY is enabled.
+   *
+   * <p>The following transports are currently supported:
+   * <ul>
+   *   <li><a href="http://www.w3.org/Protocols/rfc2616/rfc2616.html">http/1.1</a>
+   *   <li><a href="http://www.chromium.org/spdy/spdy-protocol/spdy-protocol-draft3">spdy/3</a>
+   * </ul>
+   *
+   * <p><strong>This is an evolving set.</strong> Future releases may drop
+   * support for transitional transports (like spdy/3), in favor of their
+   * successors (spdy/4 or http/2.0). The http/1.1 transport will never be
+   * dropped.
+   *
+   * <p>If multiple protocols are specified, <a
+   * href="https://technotes.googlecode.com/git/nextprotoneg.html">NPN</a> will
+   * be used to negotiate a transport. Future releases may use another mechanism
+   * (such as <a href="http://tools.ietf.org/html/draft-friedl-tls-applayerprotoneg-02">ALPN</a>)
+   * to negotiate a transport.
+   *
+   * @param transports the transports to use, in order of preference. The list
+   *     must contain "http/1.1". It must not contain null.
+   */
+  public OkHttpClient setTransports(List<String> transports) {
+    transports = Util.immutableList(transports);
+    if (!transports.contains("http/1.1")) {
+      throw new IllegalArgumentException("transports doesn't contain http/1.1: " + transports);
+    }
+    if (transports.contains(null)) {
+      throw new IllegalArgumentException("transports must not contain null");
+    }
+    this.transports = transports;
+    return this;
+  }
+
+  public List<String> getTransports() {
+    return transports;
+  }
+
   public HttpURLConnection open(URL url) {
     String protocol = url.getProtocol();
     OkHttpClient copy = copyWithDefaults();
@@ -216,9 +274,8 @@ public final class OkHttpClient {
    * each field that hasn't been explicitly configured.
    */
   private OkHttpClient copyWithDefaults() {
-    OkHttpClient result = new OkHttpClient();
+    OkHttpClient result = new OkHttpClient(this);
     result.proxy = proxy;
-    result.failedRoutes = failedRoutes;
     result.proxySelector = proxySelector != null ? proxySelector : ProxySelector.getDefault();
     result.cookieHandler = cookieHandler != null ? cookieHandler : CookieHandler.getDefault();
     result.responseCache = responseCache != null ? responseCache : ResponseCache.getDefault();
@@ -233,6 +290,7 @@ public final class OkHttpClient {
         : HttpAuthenticator.SYSTEM_DEFAULT;
     result.connectionPool = connectionPool != null ? connectionPool : ConnectionPool.getDefault();
     result.followProtocolRedirects = followProtocolRedirects;
+    result.transports = transports != null ? transports : DEFAULT_TRANSPORTS;
     return result;
   }
 }
diff --git a/okhttp/src/main/java/com/squareup/okhttp/internal/Util.java b/okhttp/src/main/java/com/squareup/okhttp/internal/Util.java
index 290e5ea9f..e19ef2178 100644
--- a/okhttp/src/main/java/com/squareup/okhttp/internal/Util.java
+++ b/okhttp/src/main/java/com/squareup/okhttp/internal/Util.java
@@ -29,6 +29,9 @@ import java.net.URI;
 import java.net.URL;
 import java.nio.ByteOrder;
 import java.nio.charset.Charset;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 import java.util.concurrent.atomic.AtomicReference;
 
 /** Junk drawer of utility methods. */
@@ -324,4 +327,9 @@ public final class Util {
     }
     return result.toString();
   }
+
+  /** Returns an immutable copy of {@code list}. */
+  public static <T> List<T> immutableList(List<T> list) {
+    return Collections.unmodifiableList(new ArrayList<T>(list));
+  }
 }
diff --git a/okhttp/src/main/java/com/squareup/okhttp/internal/http/HttpEngine.java b/okhttp/src/main/java/com/squareup/okhttp/internal/http/HttpEngine.java
index 3a93384f4..34aa9818a 100644
--- a/okhttp/src/main/java/com/squareup/okhttp/internal/http/HttpEngine.java
+++ b/okhttp/src/main/java/com/squareup/okhttp/internal/http/HttpEngine.java
@@ -278,7 +278,7 @@ public class HttpEngine {
         hostnameVerifier = policy.hostnameVerifier;
       }
       Address address = new Address(uriHost, getEffectivePort(uri), sslSocketFactory,
-          hostnameVerifier, policy.authenticator, policy.requestedProxy);
+          hostnameVerifier, policy.authenticator, policy.requestedProxy, policy.transports);
       routeSelector = new RouteSelector(address, uri, policy.proxySelector, policy.connectionPool,
           Dns.DEFAULT, policy.getFailedRoutes());
     }
diff --git a/okhttp/src/main/java/com/squareup/okhttp/internal/http/HttpURLConnectionImpl.java b/okhttp/src/main/java/com/squareup/okhttp/internal/http/HttpURLConnectionImpl.java
index 20633fff0..ee73c7fa3 100644
--- a/okhttp/src/main/java/com/squareup/okhttp/internal/http/HttpURLConnectionImpl.java
+++ b/okhttp/src/main/java/com/squareup/okhttp/internal/http/HttpURLConnectionImpl.java
@@ -93,6 +93,7 @@ public class HttpURLConnectionImpl extends HttpURLConnection {
   /* SSL configuration; necessary for HTTP requests that get redirected to HTTPS. */
   SSLSocketFactory sslSocketFactory;
   HostnameVerifier hostnameVerifier;
+  List<String> transports;
   OkAuthenticator authenticator;
   final Set<Route> failedRoutes;
 
@@ -115,6 +116,7 @@ public class HttpURLConnectionImpl extends HttpURLConnection {
     this.connectionPool = client.getConnectionPool();
     this.sslSocketFactory = client.getSslSocketFactory();
     this.hostnameVerifier = client.getHostnameVerifier();
+    this.transports = client.getTransports();
     this.authenticator = client.getAuthenticator();
     this.responseCache = responseCache;
   }
diff --git a/okhttp/src/test/java/com/squareup/okhttp/ConnectionPoolTest.java b/okhttp/src/test/java/com/squareup/okhttp/ConnectionPoolTest.java
index 28d19f430..a3a9ea87e 100644
--- a/okhttp/src/test/java/com/squareup/okhttp/ConnectionPoolTest.java
+++ b/okhttp/src/test/java/com/squareup/okhttp/ConnectionPoolTest.java
@@ -72,14 +72,14 @@ public final class ConnectionPoolTest {
   @Before public void setUp() throws Exception {
     httpServer.play();
     httpAddress = new Address(httpServer.getHostName(), httpServer.getPort(), null, null,
-        HttpAuthenticator.SYSTEM_DEFAULT, null);
+        HttpAuthenticator.SYSTEM_DEFAULT, null, Arrays.asList("spdy/3", "http/1.1"));
     httpSocketAddress = new InetSocketAddress(InetAddress.getByName(httpServer.getHostName()),
         httpServer.getPort());
 
     spdyServer.play();
-    spdyAddress =
-        new Address(spdyServer.getHostName(), spdyServer.getPort(), sslContext.getSocketFactory(),
-            new RecordingHostnameVerifier(), HttpAuthenticator.SYSTEM_DEFAULT, null);
+    spdyAddress = new Address(spdyServer.getHostName(), spdyServer.getPort(),
+        sslContext.getSocketFactory(), new RecordingHostnameVerifier(),
+        HttpAuthenticator.SYSTEM_DEFAULT, null, Arrays.asList("spdy/3", "http/1.1"));
     spdySocketAddress = new InetSocketAddress(InetAddress.getByName(spdyServer.getHostName()),
         spdyServer.getPort());
 
diff --git a/okhttp/src/test/java/com/squareup/okhttp/internal/http/RouteSelectorTest.java b/okhttp/src/test/java/com/squareup/okhttp/internal/http/RouteSelectorTest.java
index 67724ee47..687a39753 100644
--- a/okhttp/src/test/java/com/squareup/okhttp/internal/http/RouteSelectorTest.java
+++ b/okhttp/src/test/java/com/squareup/okhttp/internal/http/RouteSelectorTest.java
@@ -80,11 +80,12 @@ public final class RouteSelectorTest {
   }
 
   private final OkAuthenticator authenticator = HttpAuthenticator.SYSTEM_DEFAULT;
+  private final List<String> transports = Arrays.asList("http/1.1");
   private final FakeDns dns = new FakeDns();
   private final FakeProxySelector proxySelector = new FakeProxySelector();
 
   @Test public void singleRoute() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         Collections.EMPTY_SET);
 
@@ -102,7 +103,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void singleRouteReturnsFailedRoute() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         Collections.EMPTY_SET);
 
@@ -123,7 +124,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void explicitProxyTriesThatProxiesAddressesOnly() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, proxyA);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, proxyA, transports);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         Collections.EMPTY_SET);
 
@@ -140,7 +141,8 @@ public final class RouteSelectorTest {
   }
 
   @Test public void explicitDirectProxy() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, NO_PROXY);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, NO_PROXY,
+        transports);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         Collections.EMPTY_SET);
 
@@ -155,7 +157,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void proxySelectorReturnsNull() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
 
     proxySelector.proxies = null;
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
@@ -171,7 +173,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void proxySelectorReturnsNoProxies() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         Collections.EMPTY_SET);
 
@@ -186,7 +188,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void proxySelectorReturnsMultipleProxies() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
 
     proxySelector.proxies.add(proxyA);
     proxySelector.proxies.add(proxyB);
@@ -220,7 +222,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void proxySelectorDirectConnectionsAreSkipped() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
 
     proxySelector.proxies.add(NO_PROXY);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
@@ -237,7 +239,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void proxyDnsFailureContinuesToNextProxy() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
 
     proxySelector.proxies.add(proxyA);
     proxySelector.proxies.add(proxyB);
@@ -277,7 +279,7 @@ public final class RouteSelectorTest {
 
   @Test public void nonSslErrorAddsAllTlsModesToFailedRoute() throws Exception {
     Address address = new Address(uriHost, uriPort, socketFactory, hostnameVerifier, authenticator,
-        Proxy.NO_PROXY);
+        Proxy.NO_PROXY, transports);
     Set<Route> failedRoutes = new LinkedHashSet<Route>();
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         failedRoutes);
@@ -290,7 +292,7 @@ public final class RouteSelectorTest {
 
   @Test public void sslErrorAddsOnlyFailedTlsModeToFailedRoute() throws Exception {
     Address address = new Address(uriHost, uriPort, socketFactory, hostnameVerifier, authenticator,
-        Proxy.NO_PROXY);
+        Proxy.NO_PROXY, transports);
     Set<Route> failedRoutes = new LinkedHashSet<Route>();
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         failedRoutes);
@@ -303,7 +305,7 @@ public final class RouteSelectorTest {
 
   @Test public void multipleProxiesMultipleInetAddressesMultipleTlsModes() throws Exception {
     Address address = new Address(uriHost, uriPort, socketFactory, hostnameVerifier, authenticator,
-        null);
+        null, transports);
     proxySelector.proxies.add(proxyA);
     proxySelector.proxies.add(proxyB);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
@@ -342,7 +344,7 @@ public final class RouteSelectorTest {
 
   @Test public void failedRoutesAreLast() throws Exception {
     Address address = new Address(uriHost, uriPort, socketFactory, hostnameVerifier, authenticator,
-        Proxy.NO_PROXY);
+        Proxy.NO_PROXY, transports);
 
     Set<Route> failedRoutes = new LinkedHashSet<Route>(1);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
diff --git a/okhttp/src/test/java/com/squareup/okhttp/internal/http/URLConnectionTest.java b/okhttp/src/test/java/com/squareup/okhttp/internal/http/URLConnectionTest.java
index 5efd6b242..827648ad3 100644
--- a/okhttp/src/test/java/com/squareup/okhttp/internal/http/URLConnectionTest.java
+++ b/okhttp/src/test/java/com/squareup/okhttp/internal/http/URLConnectionTest.java
@@ -2476,6 +2476,29 @@ public final class URLConnectionTest {
     assertTrue(call, call.contains("challenges=[Basic realm=\"protected area\"]"));
   }
 
+  @Test public void setTransports() throws Exception {
+    server.enqueue(new MockResponse().setBody("A"));
+    server.play();
+    client.setTransports(Arrays.asList("http/1.1"));
+    assertContent("A", client.open(server.getUrl("/")));
+  }
+
+  @Test public void setTransportsWithoutHttp11() throws Exception {
+    try {
+      client.setTransports(Arrays.asList("spdy/3"));
+      fail();
+    } catch (IllegalArgumentException expected) {
+    }
+  }
+
+  @Test public void setTransportsWithNull() throws Exception {
+    try {
+      client.setTransports(Arrays.asList("http/1.1", null));
+      fail();
+    } catch (IllegalArgumentException expected) {
+    }
+  }
+
   /** Returns a gzipped copy of {@code bytes}. */
   public byte[] gzip(byte[] bytes) throws IOException {
     ByteArrayOutputStream bytesOut = new ByteArrayOutputStream();