diff --git a/okhttp-tests/src/test/java/com/squareup/okhttp/RequestTest.java b/okhttp-tests/src/test/java/com/squareup/okhttp/RequestTest.java
index 47c6010..3b31cc8 100644
--- a/okhttp-tests/src/test/java/com/squareup/okhttp/RequestTest.java
+++ b/okhttp-tests/src/test/java/com/squareup/okhttp/RequestTest.java
@@ -174,6 +174,16 @@
     }
   }
 
+  @Test public void headerAllowsTabOnlyInValues() throws Exception {
+    Request.Builder builder = new Request.Builder();
+    builder.header("key", "sample\tvalue");
+    try {
+      builder.header("sample\tkey", "value");
+      fail();
+    } catch (IllegalArgumentException expected) {
+    }
+  }
+
   @Test public void headerForbidsControlCharacters() throws Exception {
     assertForbiddenHeader(null);
     assertForbiddenHeader("\u0000");
@@ -185,7 +195,6 @@
     assertForbiddenHeader("a\rb");
     assertForbiddenHeader("\rb");
     // End of Android modification.
-    assertForbiddenHeader("\t");
     assertForbiddenHeader("\u001f");
     assertForbiddenHeader("\u007f");
 
diff --git a/okhttp-tests/src/test/java/com/squareup/okhttp/internal/http/HeadersTest.java b/okhttp-tests/src/test/java/com/squareup/okhttp/internal/http/HeadersTest.java
index 1f5ad6d..e4938c1 100644
--- a/okhttp-tests/src/test/java/com/squareup/okhttp/internal/http/HeadersTest.java
+++ b/okhttp-tests/src/test/java/com/squareup/okhttp/internal/http/HeadersTest.java
@@ -155,10 +155,12 @@
         .add("foo: bar")
         .add(" foo: baz") // Name leading whitespace is trimmed.
         .add("foo : bak") // Name trailing whitespace is trimmed.
+        .add("\tkey\t:\tvalue\t") // '\t' also counts as whitespace
         .add("ping:  pong  ") // Value whitespace is trimmed.
         .add("kit:kat") // Space after colon is not required.
         .build();
     assertEquals(Arrays.asList("bar", "baz", "bak"), headers.values("foo"));
+    assertEquals(Arrays.asList("value"), headers.values("key"));
     assertEquals(Arrays.asList("pong"), headers.values("ping"));
     assertEquals(Arrays.asList("kat"), headers.values("kit"));
   }
diff --git a/okhttp/src/main/java/com/squareup/okhttp/Headers.java b/okhttp/src/main/java/com/squareup/okhttp/Headers.java
index d5b4cef..9e92555 100644
--- a/okhttp/src/main/java/com/squareup/okhttp/Headers.java
+++ b/okhttp/src/main/java/com/squareup/okhttp/Headers.java
@@ -307,8 +307,8 @@
         // ANDROID-BEGIN
         // http://b/28867041 - keep things working for apps that rely on Android's (out of spec)
         // UTF-8 header encoding behavior.
-        // if (c <= '\u001f' || c >= '\u007f') {
-        if (c <= '\u001f' || c == '\u007f') {
+        // if ((c <= '\u001f' && c != '\u0009' /* htab */) || c >= '\u007f') {
+        if ((c <= '\u001f' && c != '\u0009' /* htab */) || c == '\u007f') {
         // ANDROID-END
           throw new IllegalArgumentException(String.format(
               "Unexpected char %#04x at %d in header value: %s", (int) c, i, value));