diff --git a/Lib/imghdr.py b/Lib/imghdr.py
--- a/Lib/imghdr.py
+++ b/Lib/imghdr.py
@@ -1,23 +1,25 @@
 """Recognize image file formats based on their first few bytes."""
 
 __all__ = ["what"]
 
+from os import PathLike
+
 #-------------------------#
 # Recognize image headers #
 #-------------------------#
 
 def what(file, h=None):
     f = None
     try:
         if h is None:
-            if isinstance(file, str):
+            if isinstance(file, (str, PathLike)):
                 f = open(file, 'rb')
                 h = f.read(32)
             else:
                 location = file.tell()
                 h = file.read(32)
                 file.seek(location)
         for tf in tests:
             res = tf(h, f)
             if res:
                 return res
diff --git a/Lib/test/test_imghdr.py b/Lib/test/test_imghdr.py
--- a/Lib/test/test_imghdr.py
+++ b/Lib/test/test_imghdr.py
@@ -1,13 +1,14 @@
 import imghdr
 import io
 import os
+import pathlib
 import unittest
 import warnings
 from test.support import findfile, TESTFN, unlink
 
 TEST_FILES = (
     ('python.png', 'png'),
     ('python.gif', 'gif'),
     ('python.bmp', 'bmp'),
     ('python.ppm', 'ppm'),
     ('python.pgm', 'pgm'),
@@ -42,20 +43,31 @@ class TestImghdr(unittest.TestCase):
         for filename, expected in TEST_FILES:
             filename = findfile(filename, subdir='imghdrdata')
             self.assertEqual(imghdr.what(filename), expected)
             with open(filename, 'rb') as stream:
                 self.assertEqual(imghdr.what(stream), expected)
             with open(filename, 'rb') as stream:
                 data = stream.read()
             self.assertEqual(imghdr.what(None, data), expected)
             self.assertEqual(imghdr.what(None, bytearray(data)), expected)
 
+    def test_pathlike_filename(self):
+        for filename, expected in TEST_FILES:
+            filename = findfile(filename, subdir='imghdrdata')
+            self.assertEqual(imghdr.what(pathlib.Path(filename)), expected)
+            with open(filename, 'rb') as stream:
+                self.assertEqual(imghdr.what(stream), expected)
+            with open(filename, 'rb') as stream:
+                data = stream.read()
+            self.assertEqual(imghdr.what(None, data), expected)
+            self.assertEqual(imghdr.what(None, bytearray(data)), expected)
+
     def test_register_test(self):
         def test_jumbo(h, file):
             if h.startswith(b'eggs'):
                 return 'ham'
         imghdr.tests.append(test_jumbo)
         self.addCleanup(imghdr.tests.pop)
         self.assertEqual(imghdr.what(None, b'eggs'), 'ham')
 
     def test_file_pos(self):
         with open(TESTFN, 'wb') as stream: