diff --git a/sprockets/mixins/mediatype/transcoders.py b/sprockets/mixins/mediatype/transcoders.py
index 1db8658..c852d4d 100644
--- a/sprockets/mixins/mediatype/transcoders.py
+++ b/sprockets/mixins/mediatype/transcoders.py
@@ -186,6 +186,12 @@ class MsgPackTranscoder(handlers.BinaryContentHandler):
         +-------------------------------+-------------------------------+
         | String                        | `str family`_                 |
         +-------------------------------+-------------------------------+
+        | :class:`bytes`                | `bin family`_                 |
+        +-------------------------------+-------------------------------+
+        | :class:`bytearray`            | `bin family`_                 |
+        +-------------------------------+-------------------------------+
+        | :class:`memoryview`           | `bin family`_                 |
+        +-------------------------------+-------------------------------+
         | :class:`collections.Sequence` | `array family`_               |
         +-------------------------------+-------------------------------+
         | :class:`collections.Set`      | `array family`_               |
@@ -223,16 +229,26 @@ class MsgPackTranscoder(handlers.BinaryContentHandler):
         if isinstance(datum, uuid.UUID):
             datum = str(datum)
 
+        if isinstance(datum, bytearray):
+            datum = bytes(datum)
+
+        if isinstance(datum, memoryview):
+            datum = datum.tobytes()
+
         if hasattr(datum, 'isoformat'):
             datum = datum.isoformat()
 
-        if isinstance(datum, bytes):
-            datum = datum.decode('utf-8')
-
-        if isinstance(datum, str):
+        if sys.version_info[0] < 3 and isinstance(datum, (str, unicode)):
+            if isinstance(datum, str):
+                # try to decode this into a string to make the common
+                # case work.  If we fail, then send along the bytes.
+                try:
+                    datum = datum.decode('utf-8')
+                except UnicodeDecodeError:
+                    pass
             return datum
 
-        if sys.version_info[0] < 3 and isinstance(datum, unicode):
+        if isinstance(datum, (bytes, str)):
             return datum
 
         if isinstance(datum, (collections.Sequence, collections.Set)):
diff --git a/tests.py b/tests.py
index eded984..c6c8b4b 100644
--- a/tests.py
+++ b/tests.py
@@ -48,6 +48,18 @@ def pack_string(obj):
     return prefix + payload
 
 
+def pack_bytes(payload):
+    """Optimally pack a byte string according to msgpack format"""
+    l = len(payload)
+    if l < (2 ** 8):
+        prefix = struct.pack('BB', 0xC4, l)
+    elif l < (2 ** 16):
+        prefix = struct.pack('>BH', 0xC5, l)
+    else:
+        prefix = struct.pack('>BI', 0xC6, l)
+    return prefix + payload
+
+
 class SendResponseTests(testing.AsyncHTTPTestCase):
 
     def get_app(self):
@@ -283,3 +295,21 @@ class MsgPackTranscoderTests(unittest.TestCase):
         dumped = self.transcoder.packb(now)
         self.assertEqual(self.transcoder.unpackb(dumped), now.isoformat())
         self.assertEqual(dumped, pack_string(now.isoformat()))
+
+    def test_that_bytes_are_sent_as_bytes(self):
+        data = bytes(os.urandom(127))
+        dumped = self.transcoder.packb(data)
+        self.assertEqual(self.transcoder.unpackb(dumped), data)
+        self.assertEqual(dumped, pack_bytes(data))
+
+    def test_that_bytearrays_are_sent_as_bytes(self):
+        data = bytearray(os.urandom(127))
+        dumped = self.transcoder.packb(data)
+        self.assertEqual(self.transcoder.unpackb(dumped), data)
+        self.assertEqual(dumped, pack_bytes(data))
+
+    def test_that_memoryviews_are_sent_as_bytes(self):
+        data = memoryview(os.urandom(127))
+        dumped = self.transcoder.packb(data)
+        self.assertEqual(self.transcoder.unpackb(dumped), data)
+        self.assertEqual(dumped, pack_bytes(data.tobytes()))