diff --git a/swift/common/swob.py b/swift/common/swob.py
index e0ce9ba9ba..0d272eea06 100644
--- a/swift/common/swob.py
+++ b/swift/common/swob.py
@@ -209,8 +209,12 @@ def header_to_environ_key(header_name):
     # Why the to/from wsgi dance? Headers that include something like b'\xff'
     # on the wire get translated to u'\u00ff' on py3, which gets upper()ed to
     # u'\u0178', which is nonsense in a WSGI string.
-    real_header = wsgi_to_str(header_name)
-    header_name = 'HTTP_' + str_to_wsgi(real_header.upper()).replace('-', '_')
+    # Note that we have to only get as far as bytes because something like
+    # b'\xc3\x9f' on the wire would be u'\u00df' as a native string on py3,
+    # which would upper() to 'SS'.
+    real_header = wsgi_to_bytes(header_name)
+    header_name = 'HTTP_' + bytes_to_wsgi(
+        real_header.upper()).replace('-', '_')
     if header_name == 'HTTP_CONTENT_LENGTH':
         return 'CONTENT_LENGTH'
     if header_name == 'HTTP_CONTENT_TYPE':
@@ -257,8 +261,9 @@ class HeaderEnvironProxy(MutableMapping):
 
     def keys(self):
         # See the to/from WSGI comment in header_to_environ_key
-        keys = [str_to_wsgi(wsgi_to_str(key[5:]).replace('_', '-').title())
-                for key in self.environ if key.startswith('HTTP_')]
+        keys = [
+            bytes_to_wsgi(wsgi_to_bytes(key[5:]).replace(b'_', b'-').title())
+            for key in self.environ if key.startswith('HTTP_')]
         if 'CONTENT_LENGTH' in self.environ:
             keys.append('Content-Length')
         if 'CONTENT_TYPE' in self.environ:
diff --git a/test/unit/common/test_swob.py b/test/unit/common/test_swob.py
index 9ebf95c3ce..4984ab344e 100644
--- a/test/unit/common/test_swob.py
+++ b/test/unit/common/test_swob.py
@@ -32,21 +32,26 @@ class TestHeaderEnvironProxy(unittest.TestCase):
     def test_proxy(self):
         environ = {}
         proxy = swift.common.swob.HeaderEnvironProxy(environ)
+        self.assertIs(environ, proxy.environ)
         proxy['Content-Length'] = 20
         proxy['Content-Type'] = 'text/plain'
         proxy['Something-Else'] = 'somevalue'
-        self.assertEqual(
-            proxy.environ, {'CONTENT_LENGTH': '20',
-                            'CONTENT_TYPE': 'text/plain',
-                            'HTTP_SOMETHING_ELSE': 'somevalue'})
+        # NB: WSGI strings
+        proxy['X-Object-Meta-Unicode-\xff-Bu\xc3\x9fe'] = '\xe2\x98\xb9'
+        self.assertEqual(proxy.environ, {
+            'CONTENT_LENGTH': '20',
+            'CONTENT_TYPE': 'text/plain',
+            'HTTP_SOMETHING_ELSE': 'somevalue',
+            'HTTP_X_OBJECT_META_UNICODE_\xff_BU\xc3\x9fE': '\xe2\x98\xb9'})
         self.assertEqual(proxy['content-length'], '20')
         self.assertEqual(proxy['content-type'], 'text/plain')
         self.assertEqual(proxy['something-else'], 'somevalue')
         self.assertEqual(set(['Something-Else',
+                              'X-Object-Meta-Unicode-\xff-Bu\xc3\x9fE',
                               'Content-Length', 'Content-Type']),
                          set(proxy.keys()))
         self.assertEqual(list(iter(proxy)), proxy.keys())
-        self.assertEqual(3, len(proxy))
+        self.assertEqual(4, len(proxy))
 
     def test_ignored_keys(self):
         # Constructor doesn't normalize keys
@@ -58,6 +63,8 @@ class TestHeaderEnvironProxy(unittest.TestCase):
         self.assertEqual(0, len(proxy))
         self.assertRaises(KeyError, proxy.__getitem__, key)
         self.assertNotIn(key, proxy)
+        self.assertIn(key, proxy.environ)
+        self.assertIs(environ, proxy.environ)
 
         proxy['Content-Type'] = 'text/plain'
         self.assertEqual(['Content-Type'], list(iter(proxy)))
@@ -77,6 +84,8 @@ class TestHeaderEnvironProxy(unittest.TestCase):
         del proxy['Something-Else']
         self.assertEqual(proxy.environ, {})
         self.assertEqual(0, len(proxy))
+        with self.assertRaises(KeyError):
+            del proxy['Content-Length']
 
     def test_contains(self):
         environ = {}