diff -r fcc09d9ee7d4 Lib/email/utils.py
--- a/Lib/email/utils.py	Mon Dec 19 18:51:37 2016 +0200
+++ b/Lib/email/utils.py	Thu Dec 22 10:33:41 2016 -0500
@@ -319,7 +319,7 @@
 def collapse_rfc2231_value(value, errors='replace',
                            fallback_charset='us-ascii'):
     if not isinstance(value, tuple) or len(value) != 3:
-        return unquote(value)
+        return value
     # While value comes to us as a unicode string, we need it to be a bytes
     # object.  We do not want bytes() normal utf-8 decoder, we want a straight
     # interpretation of the string as character bytes.
diff -r fcc09d9ee7d4 Lib/test/test_email/test_email.py
--- a/Lib/test/test_email/test_email.py	Mon Dec 19 18:51:37 2016 +0200
+++ b/Lib/test/test_email/test_email.py	Thu Dec 22 10:33:41 2016 -0500
@@ -5177,6 +5177,27 @@
         msg = email.message_from_string(m)
         self.assertEqual(msg.get_boundary(),
                          'This is even more ***fun*** is it not.pdf')
+    
+    def test_rfc2231_multiple_quote_boundary(self):
+        m = '''\
+Content-Type: multipart/alternative;
+\tboundary*0*="<<This%20is%20even%20more%20";
+\tboundary*1*="%2A%2A%2Afun%2A%2A%2A%20";
+\tboundary*2="is it not.pdf>>"
+
+'''
+        msg = email.message_from_string(m)
+        self.assertEqual(msg.get_boundary(),
+                         '<<This is even more ***fun*** is it not.pdf>>')
+    def test_rfc2231_multiple_quote_boundary2(self):
+        m = '''\
+Content-Type: multipart/alternative;
+\tboundary="<<This is even more >>";
+
+'''
+        msg = email.message_from_string(m)
+        self.assertEqual(msg.get_boundary(),
+                         '<<This is even more >>')
 
     def test_rfc2231_no_language_or_charset_in_charset(self):
         # This is a nonsensical charset value, but tests the code anyway