diff --git a/firebase_admin/credentials.py b/firebase_admin/credentials.py
index 1f207e483..5477e1cf7 100644
--- a/firebase_admin/credentials.py
+++ b/firebase_admin/credentials.py
@@ -15,6 +15,7 @@
 """Firebase credentials module."""
 import collections
 import json
+import pathlib
 
 import google.auth
 from google.auth.transport import requests
@@ -78,7 +79,7 @@ def __init__(self, cert):
           ValueError: If the specified certificate is invalid.
         """
         super(Certificate, self).__init__()
-        if isinstance(cert, str):
+        if _is_file_path(cert):
             with open(cert) as json_file:
                 json_data = json.load(json_file)
         elif isinstance(cert, dict):
@@ -179,7 +180,7 @@ def __init__(self, refresh_token):
           ValueError: If the refresh token configuration is invalid.
         """
         super(RefreshToken, self).__init__()
-        if isinstance(refresh_token, str):
+        if _is_file_path(refresh_token):
             with open(refresh_token) as json_file:
                 json_data = json.load(json_file)
         elif isinstance(refresh_token, dict):
@@ -212,3 +213,11 @@ def get_credential(self):
         Returns:
           google.auth.credentials.Credentials: A Google Auth credential instance."""
         return self._g_credential
+
+
+def _is_file_path(path):
+    try:
+        pathlib.Path(path)
+        return True
+    except TypeError:
+        return False
diff --git a/tests/test_credentials.py b/tests/test_credentials.py
index d78ef5192..cceb6b6f9 100644
--- a/tests/test_credentials.py
+++ b/tests/test_credentials.py
@@ -16,6 +16,7 @@
 import datetime
 import json
 import os
+import pathlib
 
 import google.auth
 from google.auth import crypt
@@ -47,6 +48,12 @@ def test_init_from_file(self):
             testutils.resource_filename('service_account.json'))
         self._verify_credential(credential)
 
+    def test_init_from_path_like(self):
+        path = pathlib.Path(testutils.resource_filename('service_account.json'))
+        credential = credentials.Certificate(path)
+        self._verify_credential(credential)
+
+
     def test_init_from_dict(self):
         parsed_json = json.loads(testutils.resource('service_account.json'))
         credential = credentials.Certificate(parsed_json)
@@ -129,6 +136,11 @@ def test_init_from_file(self):
             testutils.resource_filename('refresh_token.json'))
         self._verify_credential(credential)
 
+    def test_init_from_path_like(self):
+        path = pathlib.Path(testutils.resource_filename('refresh_token.json'))
+        credential = credentials.RefreshToken(path)
+        self._verify_credential(credential)
+
     def test_init_from_dict(self):
         parsed_json = json.loads(testutils.resource('refresh_token.json'))
         credential = credentials.RefreshToken(parsed_json)