diff -r 89821243621b Doc/library/bz2.rst
--- a/Doc/library/bz2.rst	Thu Jul 14 07:45:24 2016 +0300
+++ b/Doc/library/bz2.rst	Thu Jul 14 17:03:46 2016 +0800
@@ -37,8 +37,8 @@
    object`.
 
    As with the constructor for :class:`BZ2File`, the *filename* argument can be
-   an actual filename (a :class:`str` or :class:`bytes` object), or an existing
-   file object to read from or write to.
+   an actual filename (a :class:`str`, :class:`bytes` object or :class:`os.PathLike`
+   object), or an existing file object to read from or write to.
 
    The *mode* argument can be any of ``'r'``, ``'rb'``, ``'w'``, ``'wb'``,
    ``'x'``, ``'xb'``, ``'a'`` or ``'ab'`` for binary mode, or ``'rt'``,
@@ -61,14 +61,18 @@
    .. versionchanged:: 3.4
       The ``'x'`` (exclusive creation) mode was added.
 
+   .. versionchanged:: 3.6
+      Support added to accept objects implementing :class:`os.PathLike`.
+
 
 .. class:: BZ2File(filename, mode='r', buffering=None, compresslevel=9)
 
    Open a bzip2-compressed file in binary mode.
 
-   If *filename* is a :class:`str` or :class:`bytes` object, open the named file
-   directly. Otherwise, *filename* should be a :term:`file object`, which will
-   be used to read or write the compressed data.
+   If *filename* is a :class:`str`, :class:`bytes` or :class:`os.PathLike`
+   object, open the named file directly. Otherwise, *filename* should be
+   a :term:`file object`, which will be used to read or write the compressed
+   data.
 
    The *mode* argument can be either ``'r'`` for reading (default), ``'w'`` for
    overwriting, ``'x'`` for exclusive creation, or ``'a'`` for appending. These
@@ -128,6 +132,10 @@
       The :meth:`~io.BufferedIOBase.read` method now accepts an argument of
       ``None``.
 
+   .. versionchanged:: 3.6
+      :class:`BZ2File` constructor now accepts objects implementing
+      :class:`os.PathLike`.
+
 
 Incremental (de)compression
 ---------------------------
diff -r 89821243621b Lib/bz2.py
--- a/Lib/bz2.py	Thu Jul 14 07:45:24 2016 +0300
+++ b/Lib/bz2.py	Thu Jul 14 17:03:46 2016 +0800
@@ -91,15 +91,16 @@
         else:
             raise ValueError("Invalid mode: %r" % (mode,))
 
-        if isinstance(filename, (str, bytes)):
+        try:
             self._fp = _builtin_open(filename, mode)
             self._closefp = True
             self._mode = mode_code
-        elif hasattr(filename, "read") or hasattr(filename, "write"):
-            self._fp = filename
-            self._mode = mode_code
-        else:
-            raise TypeError("filename must be a str or bytes object, or a file")
+        except TypeError:
+            if hasattr(filename, "read") or hasattr(filename, "write"):
+                self._fp = filename
+                self._mode = mode_code
+            else:
+                raise
 
         if self._mode == _MODE_READ:
             raw = _compression.DecompressReader(self._fp,
diff -r 89821243621b Lib/test/test_bz2.py
--- a/Lib/test/test_bz2.py	Thu Jul 14 07:45:24 2016 +0300
+++ b/Lib/test/test_bz2.py	Thu Jul 14 17:03:46 2016 +0800
@@ -560,6 +560,23 @@
         with BZ2File(str_filename, "rb") as f:
             self.assertEqual(f.read(), self.DATA)
 
+    def testPathLikeFilename(self):
+        filename = self.filename
+        class PathLikeClass:
+            def __fspath__(self):
+                return filename
+        class BadPathLikeClass:
+            def __fspath__(self):
+                return BZ2File
+        with BZ2File(PathLikeClass(), "wb") as f:
+            f.write(self.DATA)
+        with BZ2File(PathLikeClass(), "rb") as f:
+            self.assertEqual(f.read(), self.DATA)
+        with BZ2File(self.filename, "rb") as f:
+            self.assertEqual(f.read(), self.DATA)
+        self.assertRaises(TypeError, BZ2File, [])
+        self.assertRaises(TypeError, BZ2File, BadPathLikeClass())
+
     def testDecompressLimited(self):
         """Decompressed data buffering should be limited"""
         bomb = bz2.compress(bytes(int(2e6)), compresslevel=9)