diff --git a/Lib/shlex.py b/Lib/shlex.py
index 4801a6c1d47bd9..595ea890433b4a 100644
--- a/Lib/shlex.py
+++ b/Lib/shlex.py
@@ -22,6 +22,10 @@ def __init__(self, instream=None, infile=None, posix=False,
                  punctuation_chars=False):
         if isinstance(instream, str):
             instream = StringIO(instream)
+        elif isinstance(instream, bytes):
+            # convert byte instreams to string
+            instream = StringIO(instream.decode("ascii", "surrogateescape"))
+
         if instream is not None:
             self.instream = instream
             self.infile = infile
@@ -312,26 +316,78 @@ def split(s, comments=False, posix=True):
     lex.whitespace_split = True
     if not comments:
         lex.commenters = ''
-    return list(lex)
+
+    if isinstance(s, bytes):
+        return [i.encode("ascii") for i in lex]
+    else:
+        return list(lex)
 
 
 def join(split_command):
     """Return a shell-escaped string from *split_command*."""
-    return ' '.join(quote(arg) for arg in split_command)
+    if len(split_command) == 0:
+        return ""
+
+    # Ensure all objects are the same type as the first one,
+    # otherwise convert and raise a warning
+    cleaned = []
+    warned = False
+
+    for command in split_command:
+        if not isinstance(command, type(split_command[0])):
+            # Check if user was warned not to mix types,
+            # warn otherwise.
+            if not warned:
+                import warnings
+                warnings.warn("All objects passed to join must be of the same type."
+                              " Converting all to {}.".format(type(split_command[0]).__name__),
+                              BytesWarning, stacklevel=2)
 
+                warned = True
 
-_find_unsafe = re.compile(r'[^\w@%+=:,./-]', re.ASCII).search
+            # Convert object to opposite type
+            if isinstance(command, bytes):
+                command = command.decode("ascii", "surrogateescape")
+            else:
+                command = command.encode("ascii")
+
+        cleaned.append(command)
+
+    # Return a joined string or bytes object
+    if isinstance(cleaned[0], bytes):
+        return b' '.join(quote(arg) for arg in cleaned)
+    else:
+        return ' '.join(quote(arg) for arg in cleaned)
+
+
+_find_unsafe_string = re.compile(r'[^\w@%+=:,./-]', re.ASCII).search
+_find_unsafe_bytes = re.compile(rb'[^\w@%+=:,./-]').search
 
 def quote(s):
     """Return a shell-escaped version of the string *s*."""
-    if not s:
-        return "''"
-    if _find_unsafe(s) is None:
-        return s
-
-    # use single quotes, and put single quotes into double quotes
-    # the string $'b is then quoted as '$'"'"'b'
-    return "'" + s.replace("'", "'\"'\"'") + "'"
+    # determine if s is bytes or string object,
+    # and check for unsafe characters
+    if isinstance(s, bytes):
+        if not s:
+            return b"''"
+
+        if _find_unsafe_bytes(s) is None:
+            return s
+
+        # use single quotes, and put single quotes into double quotes
+        # the string $'b is then quoted as '$'"'"'b'
+        return b"'" + s.replace(b"'", b"'\"'\"'") + b"'"
+
+    else:
+        if not s:
+            return "''"
+
+        if _find_unsafe_string(s) is None:
+            return s
+
+        # use single quotes, and put single quotes into double quotes
+        # the string $'b is then quoted as '$'"'"'b'
+        return "'" + s.replace("'", "'\"'\"'") + "'"
 
 
 def _print_tokens(lexer):
diff --git a/Lib/test/test_shlex.py b/Lib/test/test_shlex.py
index 3081a785204edc..5b3a5ce1945c38 100644
--- a/Lib/test/test_shlex.py
+++ b/Lib/test/test_shlex.py
@@ -171,6 +171,10 @@ def testSplitPosix(self):
         """Test data splitting with posix parser"""
         self.splitTest(self.posix_data, comments=True)
 
+    def testSplitBytes(self):
+        """Test byte objects splitting"""
+        self.assertEqual(shlex.split(b"split words"), [b"split", b"words"])
+
     def testCompat(self):
         """Test compatibility interface"""
         for i in range(len(self.data)):
@@ -339,6 +343,23 @@ def testQuote(self):
             self.assertEqual(shlex.quote("test%s'name'" % u),
                              "'test%s'\"'\"'name'\"'\"''" % u)
 
+    def testQuoteBytes(self):
+        """Test quoting of byte objects"""
+        # Copied from testQuote
+        safeunquoted = string.ascii_letters + string.digits + '@%_-+=:,./'
+        unicode_sample = '\xe9\xe0\xdf'  # e + acute accent, a + grave, sharp s
+        unsafe = '"`$\\!' + unicode_sample
+
+        self.assertEqual(shlex.quote(b''), b"''")
+        self.assertEqual(shlex.quote(safeunquoted.encode("ascii")), safeunquoted.encode("ascii"))
+        self.assertEqual(shlex.quote(b'test file name'), b"'test file name'")
+        for u in unsafe:
+            self.assertEqual(shlex.quote(('test%sname' % u).encode("utf-8")),
+                             ("'test%sname'" % u).encode("utf-8"))
+        for u in unsafe:
+            self.assertEqual(shlex.quote(("test%s'name'" % u).encode("utf-8")),
+                             ("'test%s'\"'\"'name'\"'\"''" % u).encode("utf-8"))
+
     def testJoin(self):
         for split_command, command in [
             (['a ', 'b'], "'a ' b"),
@@ -350,6 +371,9 @@ def testJoin(self):
                 joined = shlex.join(split_command)
                 self.assertEqual(joined, command)
 
+    def testEmptyJoin(self):
+        self.assertEqual(shlex.join([]), "")
+
     def testJoinRoundtrip(self):
         all_data = self.data + self.posix_data
         for command, *split_command in all_data:
@@ -358,6 +382,46 @@ def testJoinRoundtrip(self):
                 resplit = shlex.split(joined)
                 self.assertEqual(split_command, resplit)
 
+    def testJoinBytes(self):
+        self.assertEqual(shlex.join([b"Join", b"me"]), b"Join me")
+        self.assertEqual(shlex.join([b"Just_me"]), b"Just_me")
+
+    def testJoinBytesAndStrings(self):
+        """Test join can handle combinations of string and byte objects"""
+        # String then bytes
+        with self.assertWarns(BytesWarning,
+                              msg="All objects passed to join must be of the same type."
+                                  "Converting all to str."):
+            self.assertEqual(shlex.join(["str_object", b"byte_object"]), "str_object byte_object")
+
+        # Bytes then string
+        with self.assertWarns(BytesWarning,
+                              msg="All objects passed to join must be of the same type."
+                                  "Converting all to bytes."):
+            self.assertEqual(shlex.join([b"byte_object", "str_object"]), b"byte_object str_object")
+
+        # Random combination
+        with self.assertWarns(BytesWarning):
+            import random
+
+            words = "This is a fully formed sentence, to test the join functionality."
+
+            new_words = []
+            for word in words.split(" "):
+                if bool(random.randint(0, 1)):
+                    new_words.append(word.encode("ascii"))
+                else:
+                    new_words.append(word)
+
+            # ensure at least one bytes object to raise warning
+            if isinstance(new_words[2], str):
+                new_words[2] = new_words[2].encode("ascii")
+
+            if isinstance(new_words[0], bytes):
+                self.assertEqual(shlex.join(new_words), words.encode("ascii"))
+            else:
+                self.assertEqual(shlex.join(new_words), words)
+
     def testPunctuationCharsReadOnly(self):
         punctuation_chars = "/|$%^"
         shlex_instance = shlex.shlex(punctuation_chars=punctuation_chars)
diff --git a/Misc/NEWS.d/next/Library/2020-10-12-03-46-25.bpo-25567.xgfgij.rst b/Misc/NEWS.d/next/Library/2020-10-12-03-46-25.bpo-25567.xgfgij.rst
new file mode 100644
index 00000000000000..b10dc7b7ec2067
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-10-12-03-46-25.bpo-25567.xgfgij.rst
@@ -0,0 +1 @@
+Add support for bytes objects in the shlex module.