diff --git a/okhttp-tests/src/test/java/com/squareup/okhttp/internal/spdy/Spdy3ConnectionTest.java b/okhttp-tests/src/test/java/com/squareup/okhttp/internal/spdy/Spdy3ConnectionTest.java
index 110412ec2..074d9ad6f 100644
--- a/okhttp-tests/src/test/java/com/squareup/okhttp/internal/spdy/Spdy3ConnectionTest.java
+++ b/okhttp-tests/src/test/java/com/squareup/okhttp/internal/spdy/Spdy3ConnectionTest.java
@@ -941,8 +941,9 @@ public final class Spdy3ConnectionTest {
     sink.write(new Buffer().writeUtf8("abcde"), 5);
     stream.writeTimeout().timeout(500, TimeUnit.MILLISECONDS);
     long startNanos = System.nanoTime();
+    sink.write(new Buffer().writeUtf8("f"), 1);
     try {
-      sink.write(new Buffer().writeUtf8("f"), 1); // This will time out waiting on the write window.
+      sink.flush(); // This will time out waiting on the write window.
       fail();
     } catch (InterruptedIOException expected) {
     }
@@ -957,6 +958,31 @@ public final class Spdy3ConnectionTest {
     assertEquals(TYPE_RST_STREAM, peer.takeFrame().type);
   }
 
+  @Test public void outgoingWritesAreBatched() throws Exception {
+    // write the mocking script
+    peer.acceptFrame(); // SYN_STREAM
+    peer.sendFrame().synReply(false, 1, headerEntries("a", "android"));
+    peer.acceptFrame(); // DATA
+    peer.play();
+
+    // play it back
+    SpdyConnection connection = connection(peer, SPDY3);
+    SpdyStream stream = connection.newStream(headerEntries("b", "banana"), true, true);
+
+    // two outgoing writes
+    Sink sink = stream.getSink();
+    sink.write(new Buffer().writeUtf8("abcde"), 5);
+    sink.write(new Buffer().writeUtf8("fghij"), 5);
+    sink.close();
+
+    // verify the peer received one incoming frame
+    assertEquals(TYPE_HEADERS, peer.takeFrame().type);
+    MockSpdyPeer.InFrame data = peer.takeFrame();
+    assertEquals(TYPE_DATA, data.type);
+    assertTrue(Arrays.equals("abcdefghij".getBytes("UTF-8"), data.data));
+    assertTrue(data.inFinished);
+  }
+
   @Test public void headers() throws Exception {
     // write the mocking script
     peer.acceptFrame(); // SYN_STREAM
diff --git a/okhttp/src/main/java/com/squareup/okhttp/internal/spdy/SpdyStream.java b/okhttp/src/main/java/com/squareup/okhttp/internal/spdy/SpdyStream.java
index 331536d37..abc5df651 100644
--- a/okhttp/src/main/java/com/squareup/okhttp/internal/spdy/SpdyStream.java
+++ b/okhttp/src/main/java/com/squareup/okhttp/internal/spdy/SpdyStream.java
@@ -53,7 +53,6 @@ public final class SpdyStream {
 
   private final int id;
   private final SpdyConnection connection;
-  private long readTimeoutMillis = 0;
 
   /** Headers sent by the stream initiator. Immutable and non null. */
   private final List<Header> requestHeaders;
@@ -468,6 +467,14 @@ public final class SpdyStream {
    * thread safe.
    */
   final class SpdyDataSink implements Sink {
+    private static final long EMIT_BUFFER_SIZE = 16384;
+
+    /**
+     * Buffer of outgoing data. This batches writes of small writes into this sink as larges
+     * frames written to the outgoing connection. Batching saves the (small) framing overhead.
+     */
+    private final Buffer sendBuffer = new Buffer();
+
     private boolean closed;
 
     /**
@@ -478,26 +485,34 @@ public final class SpdyStream {
 
     @Override public void write(Buffer source, long byteCount) throws IOException {
       assert (!Thread.holdsLock(SpdyStream.this));
-      while (byteCount > 0) {
-        long toWrite;
-        synchronized (SpdyStream.this) {
-          writeTimeout.enter();
-          try {
-            while (bytesLeftInWriteWindow <= 0 && !finished && !closed && errorCode == null) {
-              waitForIo(); // Wait until we receive a WINDOW_UPDATE.
-            }
-          } finally {
-            writeTimeout.exitAndThrowIfTimedOut();
-          }
+      sendBuffer.write(source, byteCount);
+      while (sendBuffer.size() >= EMIT_BUFFER_SIZE) {
+        emitDataFrame(false);
+      }
+    }
 
-          checkOutNotClosed(); // Kick out if the stream was reset or closed while waiting.
-          toWrite = Math.min(bytesLeftInWriteWindow, byteCount);
-          bytesLeftInWriteWindow -= toWrite;
+    /**
+     * Emit a single data frame to the connection. The frame's size be limited by this stream's
+     * write window. This method will block until the write window is nonempty.
+     */
+    private void emitDataFrame(boolean outFinished) throws IOException {
+      long toWrite;
+      synchronized (SpdyStream.this) {
+        writeTimeout.enter();
+        try {
+          while (bytesLeftInWriteWindow <= 0 && !finished && !closed && errorCode == null) {
+            waitForIo(); // Wait until we receive a WINDOW_UPDATE.
+          }
+        } finally {
+          writeTimeout.exitAndThrowIfTimedOut();
         }
 
-        byteCount -= toWrite;
-        connection.writeData(id, false, source, toWrite);
+        checkOutNotClosed(); // Kick out if the stream was reset or closed while waiting.
+        toWrite = Math.min(bytesLeftInWriteWindow, sendBuffer.size());
+        bytesLeftInWriteWindow -= toWrite;
       }
+
+      connection.writeData(id, outFinished && toWrite == sendBuffer.size(), sendBuffer, toWrite);
     }
 
     @Override public void flush() throws IOException {
@@ -505,6 +520,9 @@ public final class SpdyStream {
       synchronized (SpdyStream.this) {
         checkOutNotClosed();
       }
+      while (sendBuffer.size() > 0) {
+        emitDataFrame(false);
+      }
       connection.flush();
     }
 
@@ -518,7 +536,15 @@ public final class SpdyStream {
         if (closed) return;
       }
       if (!sink.finished) {
-        connection.writeData(id, true, null, 0);
+        // Emit the remaining data, setting the END_STREAM flag on the last frame.
+        if (sendBuffer.size() > 0) {
+          while (sendBuffer.size() > 0) {
+            emitDataFrame(true);
+          }
+        } else {
+          // Send an empty frame just so we can set the END_STREAM flag.
+          connection.writeData(id, true, null, 0);
+        }
       }
       synchronized (SpdyStream.this) {
         closed = true;