diff --git a/swift/common/middleware/s3api/controllers/bucket.py b/swift/common/middleware/s3api/controllers/bucket.py
index 29c6da4634..311925e3c8 100644
--- a/swift/common/middleware/s3api/controllers/bucket.py
+++ b/swift/common/middleware/s3api/controllers/bucket.py
@@ -234,10 +234,15 @@ class BucketController(Controller):
                     # SLOs may be in something *close* to the MU format
                     etag = '"%s-N"' % o['slo_etag'].strip('"')
                 else:
-                    # Normal objects just use the MD5
-                    etag = '"%s"' % o['hash']
-                    # This also catches sufficiently-old SLOs, but we have
-                    # no way to identify those from container listings
+                    etag = o['hash']
+                    if len(etag) < 2 or etag[::len(etag) - 1] != '""':
+                        # Normal objects just use the MD5
+                        etag = '"%s"' % o['hash']
+                        # This also catches sufficiently-old SLOs, but we have
+                        # no way to identify those from container listings
+                    # Otherwise, somebody somewhere (proxyfs, maybe?) made this
+                    # look like an RFC-compliant ETag; we don't need to
+                    # quote-wrap.
                 SubElement(contents, 'ETag').text = etag
                 SubElement(contents, 'Size').text = str(o['bytes'])
                 if fetch_owner or listing_type != 'version-2':
diff --git a/test/unit/common/middleware/s3api/test_bucket.py b/test/unit/common/middleware/s3api/test_bucket.py
index 9ca26ef97c..b75ae1d5cd 100644
--- a/test/unit/common/middleware/s3api/test_bucket.py
+++ b/test/unit/common/middleware/s3api/test_bucket.py
@@ -34,6 +34,9 @@ from test.unit.common.middleware.s3api import S3ApiTestCase
 from test.unit.common.middleware.s3api.test_s3_acl import s3acl
 from test.unit.common.middleware.s3api.helpers import UnreadableInput
 
+# Example etag from ProxyFS; note that it is already quote-wrapped
+PFS_ETAG = '"pfsv2/AUTH_test/01234567/89abcdef-32"'
+
 
 class TestS3ApiBucket(S3ApiTestCase):
     def setup_objects(self):
@@ -43,6 +46,8 @@ class TestS3ApiBucket(S3ApiTestCase):
                         (u'lily-\u062a', '2011-01-05T02:19:14.275290', 0, 390),
                         ('mu', '2011-01-05T02:19:14.275290',
                          'md5-of-the-manifest; s3_etag=0', '3909'),
+                        ('pfs-obj', '2011-01-05T02:19:14.275290',
+                         PFS_ETAG, '3909'),
                         ('slo', '2011-01-05T02:19:14.275290',
                          'md5-of-the-manifest', '3909'),
                         ('with space', '2011-01-05T02:19:14.275290', 0, 390),
@@ -52,7 +57,7 @@ class TestS3ApiBucket(S3ApiTestCase):
             {'name': item[0], 'last_modified': str(item[1]),
              'hash': str(item[2]), 'bytes': str(item[3])}
             for item in self.objects]
-        objects[5]['slo_etag'] = '"0"'
+        objects[6]['slo_etag'] = '"0"'
         object_list = json.dumps(objects)
 
         self.prefixes = ['rose', 'viola', 'lily']
@@ -171,6 +176,7 @@ class TestS3ApiBucket(S3ApiTestCase):
                              o.find('./LastModified').text)
         self.assertEqual(items, [
             (i[0].encode('utf-8') if six.PY2 else i[0],
+             PFS_ETAG if i[0] == 'pfs-obj' else
              '"0-N"' if i[0] == 'slo' else '"0"')
             for i in self.objects])
 
@@ -196,7 +202,9 @@ class TestS3ApiBucket(S3ApiTestCase):
                              o.find('./LastModified').text)
 
         self.assertEqual(items, [
-            (quote(i[0].encode('utf-8')), '"0-N"' if i[0] == 'slo' else '"0"')
+            (quote(i[0].encode('utf-8')),
+             PFS_ETAG if i[0] == 'pfs-obj' else
+             '"0-N"' if i[0] == 'slo' else '"0"')
             for i in self.objects])
 
     def test_bucket_GET_subdir(self):
@@ -576,7 +584,8 @@ class TestS3ApiBucket(S3ApiTestCase):
         self.assertEqual([v.find('./LastModified').text for v in versions],
                          [v[1][:-3] + 'Z' for v in objects])
         self.assertEqual([v.find('./ETag').text for v in versions],
-                         ['"0-N"' if v[0] == 'slo' else '"0"'
+                         [PFS_ETAG if v[0] == 'pfs-obj' else
+                          '"0-N"' if v[0] == 'slo' else '"0"'
                           for v in objects])
         self.assertEqual([v.find('./Size').text for v in versions],
                          [str(v[3]) for v in objects])