diff --git a/firebase_admin/__init__.py b/firebase_admin/__init__.py
index eae68bd06..400396266 100644
--- a/firebase_admin/__init__.py
+++ b/firebase_admin/__init__.py
@@ -18,8 +18,6 @@
 import os
 import threading
 
-import six
-
 from firebase_admin import credentials
 from firebase_admin.__about__ import __version__
 
@@ -126,7 +124,7 @@ def get_app(name=_DEFAULT_APP_NAME):
       ValueError: If the specified name is not a string, or if the specified
           app does not exist.
     """
-    if not isinstance(name, six.string_types):
+    if not isinstance(name, str):
         raise ValueError('Illegal app name argument type: "{}". App name '
                          'must be a string.'.format(type(name)))
     with _apps_lock:
@@ -203,7 +201,7 @@ def __init__(self, name, credential, options):
         Raises:
           ValueError: If an argument is None or invalid.
         """
-        if not name or not isinstance(name, six.string_types):
+        if not name or not isinstance(name, str):
             raise ValueError('Illegal Firebase app name "{0}" provided. App name must be a '
                              'non-empty string.'.format(name))
         self._name = name
@@ -221,7 +219,7 @@ def __init__(self, name, credential, options):
 
     @classmethod
     def _validate_project_id(cls, project_id):
-        if project_id is not None and not isinstance(project_id, six.string_types):
+        if project_id is not None and not isinstance(project_id, str):
             raise ValueError(
                 'Invalid project ID: "{0}". project ID must be a string.'.format(project_id))
 
@@ -286,7 +284,7 @@ def _get_service(self, name, initializer):
         Raises:
           ValueError: If the provided name is invalid, or if the App is already deleted.
         """
-        if not name or not isinstance(name, six.string_types):
+        if not name or not isinstance(name, str):
             raise ValueError(
                 'Illegal name argument: "{0}". Name must be a non-empty string.'.format(name))
         with self._lock:
diff --git a/firebase_admin/_auth_utils.py b/firebase_admin/_auth_utils.py
index b54e7d480..2f7383c0b 100644
--- a/firebase_admin/_auth_utils.py
+++ b/firebase_admin/_auth_utils.py
@@ -16,9 +16,7 @@
 
 import json
 import re
-
-import six
-from six.moves import urllib
+from urllib import parse
 
 from firebase_admin import exceptions
 from firebase_admin import _utils
@@ -35,7 +33,7 @@
 def validate_uid(uid, required=False):
     if uid is None and not required:
         return None
-    if not isinstance(uid, six.string_types) or not uid or len(uid) > 128:
+    if not isinstance(uid, str) or not uid or len(uid) > 128:
         raise ValueError(
             'Invalid uid: "{0}". The uid must be a non-empty string with no more than 128 '
             'characters.'.format(uid))
@@ -44,7 +42,7 @@ def validate_uid(uid, required=False):
 def validate_email(email, required=False):
     if email is None and not required:
         return None
-    if not isinstance(email, six.string_types) or not email:
+    if not isinstance(email, str) or not email:
         raise ValueError(
             'Invalid email: "{0}". Email must be a non-empty string.'.format(email))
     parts = email.split('@')
@@ -61,7 +59,7 @@ def validate_phone(phone, required=False):
     """
     if phone is None and not required:
         return None
-    if not isinstance(phone, six.string_types) or not phone:
+    if not isinstance(phone, str) or not phone:
         raise ValueError('Invalid phone number: "{0}". Phone number must be a non-empty '
                          'string.'.format(phone))
     if not phone.startswith('+') or not re.search('[a-zA-Z0-9]', phone):
@@ -72,7 +70,7 @@ def validate_phone(phone, required=False):
 def validate_password(password, required=False):
     if password is None and not required:
         return None
-    if not isinstance(password, six.string_types) or len(password) < 6:
+    if not isinstance(password, str) or len(password) < 6:
         raise ValueError(
             'Invalid password string. Password must be a string at least 6 characters long.')
     return password
@@ -80,14 +78,14 @@ def validate_password(password, required=False):
 def validate_bytes(value, label, required=False):
     if value is None and not required:
         return None
-    if not isinstance(value, six.binary_type) or not value:
+    if not isinstance(value, bytes) or not value:
         raise ValueError('{0} must be a non-empty byte sequence.'.format(label))
     return value
 
 def validate_display_name(display_name, required=False):
     if display_name is None and not required:
         return None
-    if not isinstance(display_name, six.string_types) or not display_name:
+    if not isinstance(display_name, str) or not display_name:
         raise ValueError(
             'Invalid display name: "{0}". Display name must be a non-empty '
             'string.'.format(display_name))
@@ -96,7 +94,7 @@ def validate_display_name(display_name, required=False):
 def validate_provider_id(provider_id, required=True):
     if provider_id is None and not required:
         return None
-    if not isinstance(provider_id, six.string_types) or not provider_id:
+    if not isinstance(provider_id, str) or not provider_id:
         raise ValueError(
             'Invalid provider ID: "{0}". Provider ID must be a non-empty '
             'string.'.format(provider_id))
@@ -106,12 +104,12 @@ def validate_photo_url(photo_url, required=False):
     """Parses and validates the given URL string."""
     if photo_url is None and not required:
         return None
-    if not isinstance(photo_url, six.string_types) or not photo_url:
+    if not isinstance(photo_url, str) or not photo_url:
         raise ValueError(
             'Invalid photo URL: "{0}". Photo URL must be a non-empty '
             'string.'.format(photo_url))
     try:
-        parsed = urllib.parse.urlparse(photo_url)
+        parsed = parse.urlparse(photo_url)
         if not parsed.netloc:
             raise ValueError('Malformed photo URL: "{0}".'.format(photo_url))
         return photo_url
diff --git a/firebase_admin/_messaging_encoder.py b/firebase_admin/_messaging_encoder.py
index aefaf3e2f..c4da53f0d 100644
--- a/firebase_admin/_messaging_encoder.py
+++ b/firebase_admin/_messaging_encoder.py
@@ -20,8 +20,6 @@
 import numbers
 import re
 
-import six
-
 import firebase_admin._messaging_utils as _messaging_utils
 
 
@@ -99,7 +97,7 @@ def check_string(cls, label, value, non_empty=False):
         """Checks if the given value is a string."""
         if value is None:
             return None
-        if not isinstance(value, six.string_types):
+        if not isinstance(value, str):
             if non_empty:
                 raise ValueError('{0} must be a non-empty string.'.format(label))
             raise ValueError('{0} must be a string.'.format(label))
@@ -122,10 +120,10 @@ def check_string_dict(cls, label, value):
             return None
         if not isinstance(value, dict):
             raise ValueError('{0} must be a dictionary.'.format(label))
-        non_str = [k for k in value if not isinstance(k, six.string_types)]
+        non_str = [k for k in value if not isinstance(k, str)]
         if non_str:
             raise ValueError('{0} must not contain non-string keys.'.format(label))
-        non_str = [v for v in value.values() if not isinstance(v, six.string_types)]
+        non_str = [v for v in value.values() if not isinstance(v, str)]
         if non_str:
             raise ValueError('{0} must not contain non-string values.'.format(label))
         return value
@@ -137,7 +135,7 @@ def check_string_list(cls, label, value):
             return None
         if not isinstance(value, list):
             raise ValueError('{0} must be a list of strings.'.format(label))
-        non_str = [k for k in value if not isinstance(k, six.string_types)]
+        non_str = [k for k in value if not isinstance(k, str)]
         if non_str:
             raise ValueError('{0} must not contain non-string values.'.format(label))
         return value
@@ -570,7 +568,7 @@ def encode_aps_sound(cls, sound):
         """Encodes an APNs sound configuration into JSON."""
         if sound is None:
             return None
-        if sound and isinstance(sound, six.string_types):
+        if sound and isinstance(sound, str):
             return sound
         if not isinstance(sound, _messaging_utils.CriticalSound):
             raise ValueError(
@@ -593,7 +591,7 @@ def encode_aps_alert(cls, alert):
         """Encodes an ``ApsAlert`` instance into JSON."""
         if alert is None:
             return None
-        if isinstance(alert, six.string_types):
+        if isinstance(alert, str):
             return alert
         if not isinstance(alert, _messaging_utils.ApsAlert):
             raise ValueError('Aps.alert must be a string or an instance of ApsAlert class.')
diff --git a/firebase_admin/_token_gen.py b/firebase_admin/_token_gen.py
index 471630cca..4234bfa7b 100644
--- a/firebase_admin/_token_gen.py
+++ b/firebase_admin/_token_gen.py
@@ -19,7 +19,6 @@
 
 import cachecontrol
 import requests
-import six
 from google.auth import credentials
 from google.auth import iam
 from google.auth import jwt
@@ -149,7 +148,7 @@ def create_custom_token(self, uid, developer_claims=None):
                                          ', '.join(disallowed_keys)))
                 raise ValueError(error_message)
 
-        if not uid or not isinstance(uid, six.string_types) or len(uid) > 128:
+        if not uid or not isinstance(uid, str) or len(uid) > 128:
             raise ValueError('uid must be a string between 1 and 128 characters.')
 
         signing_provider = self.signing_provider
@@ -174,8 +173,8 @@ def create_custom_token(self, uid, developer_claims=None):
 
     def create_session_cookie(self, id_token, expires_in):
         """Creates a session cookie from the provided ID token."""
-        id_token = id_token.decode('utf-8') if isinstance(id_token, six.binary_type) else id_token
-        if not isinstance(id_token, six.text_type) or not id_token:
+        id_token = id_token.decode('utf-8') if isinstance(id_token, bytes) else id_token
+        if not isinstance(id_token, str) or not id_token:
             raise ValueError(
                 'Illegal ID token provided: {0}. ID token must be a non-empty '
                 'string.'.format(id_token))
@@ -256,8 +255,8 @@ def __init__(self, **kwargs):
 
     def verify(self, token, request):
         """Verifies the signature and data for the provided JWT."""
-        token = token.encode('utf-8') if isinstance(token, six.text_type) else token
-        if not isinstance(token, six.binary_type) or not token:
+        token = token.encode('utf-8') if isinstance(token, str) else token
+        if not isinstance(token, bytes) or not token:
             raise ValueError(
                 'Illegal {0} provided: {1}. {0} must be a non-empty '
                 'string.'.format(self.short_name, token))
@@ -308,7 +307,7 @@ def verify(self, token, request):
                 'Firebase {0} has incorrect "iss" (issuer) claim. Expected "{1}" but '
                 'got "{2}". {3} {4}'.format(self.short_name, expected_issuer, issuer,
                                             project_id_match_msg, verify_id_token_msg))
-        elif subject is None or not isinstance(subject, six.string_types):
+        elif subject is None or not isinstance(subject, str):
             error_message = (
                 'Firebase {0} has no "sub" (subject) claim. '
                 '{1}'.format(self.short_name, verify_id_token_msg))
diff --git a/firebase_admin/_user_mgt.py b/firebase_admin/_user_mgt.py
index 5b33abb39..533259e70 100644
--- a/firebase_admin/_user_mgt.py
+++ b/firebase_admin/_user_mgt.py
@@ -16,9 +16,9 @@
 
 import base64
 import json
+from urllib import parse
+
 import requests
-import six
-from six.moves import urllib
 
 from firebase_admin import _auth_utils
 from firebase_admin import _user_import
@@ -397,7 +397,7 @@ def encode_action_code_settings(settings):
         raise ValueError("Dynamic action links url is mandatory")
 
     try:
-        parsed = urllib.parse.urlparse(settings.url)
+        parsed = parse.urlparse(settings.url)
         if not parsed.netloc:
             raise ValueError('Malformed dynamic action links url: "{0}".'.format(settings.url))
         parameters['continueUrl'] = settings.url
@@ -413,14 +413,14 @@ def encode_action_code_settings(settings):
 
     # dynamic_link_domain
     if settings.dynamic_link_domain is not None:
-        if not isinstance(settings.dynamic_link_domain, six.string_types):
+        if not isinstance(settings.dynamic_link_domain, str):
             raise ValueError('Invalid value provided for dynamic_link_domain: {0}'
                              .format(settings.dynamic_link_domain))
         parameters['dynamicLinkDomain'] = settings.dynamic_link_domain
 
     # ios_bundle_id
     if settings.ios_bundle_id is not None:
-        if not isinstance(settings.ios_bundle_id, six.string_types):
+        if not isinstance(settings.ios_bundle_id, str):
             raise ValueError('Invalid value provided for ios_bundle_id: {0}'
                              .format(settings.ios_bundle_id))
         parameters['iosBundleId'] = settings.ios_bundle_id
@@ -431,13 +431,13 @@ def encode_action_code_settings(settings):
         raise ValueError("Android package name is required when specifying other Android settings")
 
     if settings.android_package_name is not None:
-        if not isinstance(settings.android_package_name, six.string_types):
+        if not isinstance(settings.android_package_name, str):
             raise ValueError('Invalid value provided for android_package_name: {0}'
                              .format(settings.android_package_name))
         parameters['androidPackageName'] = settings.android_package_name
 
     if settings.android_minimum_version is not None:
-        if not isinstance(settings.android_minimum_version, six.string_types):
+        if not isinstance(settings.android_minimum_version, str):
             raise ValueError('Invalid value provided for android_minimum_version: {0}'
                              .format(settings.android_minimum_version))
         parameters['androidMinimumVersion'] = settings.android_minimum_version
@@ -486,7 +486,7 @@ def get_user(self, **kwargs):
     def list_users(self, page_token=None, max_results=MAX_LIST_USERS_RESULTS):
         """Retrieves a batch of users."""
         if page_token is not None:
-            if not isinstance(page_token, six.string_types) or not page_token:
+            if not isinstance(page_token, str) or not page_token:
                 raise ValueError('Page token must be a non-empty string.')
         if not isinstance(max_results, int):
             raise ValueError('Max results must be an integer.')
diff --git a/firebase_admin/_utils.py b/firebase_admin/_utils.py
index 7ec1b8fb8..2c4cec868 100644
--- a/firebase_admin/_utils.py
+++ b/firebase_admin/_utils.py
@@ -14,13 +14,13 @@
 
 """Internal utilities common to all modules."""
 
+import io
 import json
 import socket
 
 import googleapiclient
 import httplib2
 import requests
-import six
 
 import firebase_admin
 from firebase_admin import exceptions
@@ -255,7 +255,7 @@ def handle_googleapiclient_error(error, message=None, code=None, http_response=N
 def _http_response_from_googleapiclient_error(error):
     """Creates a requests HTTP Response object from the given googleapiclient error."""
     resp = requests.models.Response()
-    resp.raw = six.BytesIO(error.content)
+    resp.raw = io.BytesIO(error.content)
     resp.status_code = error.resp.status
     return resp
 
diff --git a/firebase_admin/credentials.py b/firebase_admin/credentials.py
index e930675bd..8f9c504f0 100644
--- a/firebase_admin/credentials.py
+++ b/firebase_admin/credentials.py
@@ -15,7 +15,6 @@
 """Firebase credentials module."""
 import collections
 import json
-import six
 
 import google.auth
 from google.auth.transport import requests
@@ -79,7 +78,7 @@ def __init__(self, cert):
           ValueError: If the specified certificate is invalid.
         """
         super(Certificate, self).__init__()
-        if isinstance(cert, six.string_types):
+        if isinstance(cert, str):
             with open(cert) as json_file:
                 json_data = json.load(json_file)
         elif isinstance(cert, dict):
@@ -180,7 +179,7 @@ def __init__(self, refresh_token):
           ValueError: If the refresh token configuration is invalid.
         """
         super(RefreshToken, self).__init__()
-        if isinstance(refresh_token, six.string_types):
+        if isinstance(refresh_token, str):
             with open(refresh_token) as json_file:
                 json_data = json.load(json_file)
         elif isinstance(refresh_token, dict):
diff --git a/firebase_admin/db.py b/firebase_admin/db.py
index 2fb8b3a74..9092a955c 100644
--- a/firebase_admin/db.py
+++ b/firebase_admin/db.py
@@ -25,11 +25,10 @@
 import os
 import sys
 import threading
+from urllib import parse
 
 import google.auth
 import requests
-import six
-from six.moves import urllib
 
 import firebase_admin
 from firebase_admin import exceptions
@@ -73,7 +72,7 @@ def reference(path='/', app=None, url=None):
 
 def _parse_path(path):
     """Parses a path string into a set of segments."""
-    if not isinstance(path, six.string_types):
+    if not isinstance(path, str):
         raise ValueError('Invalid path: "{0}". Path must be a string.'.format(path))
     if any(ch in path for ch in _INVALID_PATH_CHARACTERS):
         raise ValueError(
@@ -185,7 +184,7 @@ def child(self, path):
         Raises:
           ValueError: If the child path is not a string, not well-formed or begins with '/'.
         """
-        if not path or not isinstance(path, six.string_types):
+        if not path or not isinstance(path, str):
             raise ValueError(
                 'Invalid path argument: "{0}". Path must be a non-empty string.'.format(path))
         if path.startswith('/'):
@@ -239,7 +238,7 @@ def get_if_changed(self, etag):
           ValueError: If the ETag is not a string.
           FirebaseError: If an error occurs while communicating with the remote database server.
         """
-        if not isinstance(etag, six.string_types):
+        if not isinstance(etag, str):
             raise ValueError('ETag must be a string.')
 
         resp = self._client.request('get', self._add_suffix(), headers={'if-none-match': etag})
@@ -285,7 +284,7 @@ def set_if_unchanged(self, expected_etag, value):
           FirebaseError: If an error occurs while communicating with the remote database server.
         """
         # pylint: disable=missing-raises-doc
-        if not isinstance(expected_etag, six.string_types):
+        if not isinstance(expected_etag, str):
             raise ValueError('Expected ETag must be a string.')
         if value is None:
             raise ValueError('Value must not be none.')
@@ -488,7 +487,7 @@ class Query:
 
     def __init__(self, **kwargs):
         order_by = kwargs.pop('order_by')
-        if not order_by or not isinstance(order_by, six.string_types):
+        if not order_by or not isinstance(order_by, str):
             raise ValueError('order_by field must be a non-empty string')
         if order_by not in _RESERVED_FILTERS:
             if order_by.startswith('/'):
@@ -704,7 +703,7 @@ def _get_index_type(cls, index):
             return cls._type_bool_true
         if isinstance(index, (int, float)):
             return cls._type_numeric
-        if isinstance(index, six.string_types):
+        if isinstance(index, str):
             return cls._type_string
 
         return cls._type_object
@@ -825,11 +824,11 @@ def _parse_db_url(cls, url, emulator_host=None):
         base URL will use emulator_host instead. emulator_host is ignored
         if url is already an emulator URL.
         """
-        if not url or not isinstance(url, six.string_types):
+        if not url or not isinstance(url, str):
             raise ValueError(
                 'Invalid database URL: "{0}". Database URL must be a non-empty '
                 'URL string.'.format(url))
-        parsed_url = urllib.parse.urlparse(url)
+        parsed_url = parse.urlparse(url)
         if parsed_url.netloc.endswith('.firebaseio.com'):
             return cls._parse_production_url(parsed_url, emulator_host)
 
@@ -857,7 +856,7 @@ def _parse_production_url(cls, parsed_url, emulator_host):
     @classmethod
     def _parse_emulator_url(cls, parsed_url):
         """Parses emulator URL like http://localhost:8080/?ns=foo-bar"""
-        query_ns = urllib.parse.parse_qs(parsed_url.query).get('ns')
+        query_ns = parse.parse_qs(parsed_url.query).get('ns')
         if parsed_url.scheme != 'http' or (not query_ns or len(query_ns) != 1 or not query_ns[0]):
             raise ValueError(
                 'Invalid database URL: "{0}". Database URL must be a valid URL to a '
diff --git a/firebase_admin/instance_id.py b/firebase_admin/instance_id.py
index f90d058cc..604158d9c 100644
--- a/firebase_admin/instance_id.py
+++ b/firebase_admin/instance_id.py
@@ -18,7 +18,6 @@
 """
 
 import requests
-import six
 
 from firebase_admin import _http_client
 from firebase_admin import _utils
@@ -80,7 +79,7 @@ def __init__(self, app):
             credential=app.credential.get_credential(), base_url=_IID_SERVICE_URL)
 
     def delete_instance_id(self, instance_id):
-        if not isinstance(instance_id, six.string_types) or not instance_id:
+        if not isinstance(instance_id, str) or not instance_id:
             raise ValueError('Instance ID must be a non-empty string.')
         path = 'project/{0}/instanceId/{1}'.format(self._project_id, instance_id)
         try:
diff --git a/firebase_admin/messaging.py b/firebase_admin/messaging.py
index 71366e5c4..9262751a1 100644
--- a/firebase_admin/messaging.py
+++ b/firebase_admin/messaging.py
@@ -15,12 +15,11 @@
 """Firebase Cloud Messaging module."""
 
 import json
-import requests
-import six
 
 import googleapiclient
 from googleapiclient import http
 from googleapiclient import _auth
+import requests
 
 import firebase_admin
 from firebase_admin import _http_client
@@ -395,15 +394,15 @@ def batch_callback(_, response, error):
 
     def make_topic_management_request(self, tokens, topic, operation):
         """Invokes the IID service for topic management functionality."""
-        if isinstance(tokens, six.string_types):
+        if isinstance(tokens, str):
             tokens = [tokens]
         if not isinstance(tokens, list) or not tokens:
             raise ValueError('Tokens must be a string or a non-empty list of strings.')
-        invalid_str = [t for t in tokens if not isinstance(t, six.string_types) or not t]
+        invalid_str = [t for t in tokens if not isinstance(t, str) or not t]
         if invalid_str:
             raise ValueError('Tokens must be non-empty strings.')
 
-        if not isinstance(topic, six.string_types) or not topic:
+        if not isinstance(topic, str) or not topic:
             raise ValueError('Topic must be a non-empty string.')
         if not topic.startswith('/topics/'):
             topic = '/topics/{0}'.format(topic)
diff --git a/firebase_admin/project_management.py b/firebase_admin/project_management.py
index 076542bda..91aa1eebb 100644
--- a/firebase_admin/project_management.py
+++ b/firebase_admin/project_management.py
@@ -22,7 +22,6 @@
 import time
 
 import requests
-import six
 
 import firebase_admin
 from firebase_admin import exceptions
@@ -117,13 +116,13 @@ def create_ios_app(bundle_id, display_name=None, app=None):
 
 
 def _check_is_string_or_none(obj, field_name):
-    if obj is None or isinstance(obj, six.string_types):
+    if obj is None or isinstance(obj, str):
         return obj
     raise ValueError('{0} must be a string.'.format(field_name))
 
 
 def _check_is_nonempty_string(obj, field_name):
-    if isinstance(obj, six.string_types) and obj:
+    if isinstance(obj, str) and obj:
         return obj
     raise ValueError('{0} must be a non-empty string.'.format(field_name))
 
diff --git a/firebase_admin/storage.py b/firebase_admin/storage.py
index a080b31ef..16f48e273 100644
--- a/firebase_admin/storage.py
+++ b/firebase_admin/storage.py
@@ -25,8 +25,6 @@
     raise ImportError('Failed to import the Cloud Storage library for Python. Make sure '
                       'to install the "google-cloud-storage" module.')
 
-import six
-
 from firebase_admin import _utils
 
 
@@ -77,7 +75,7 @@ def bucket(self, name=None):
                 'Storage bucket name not specified. Specify the bucket name via the '
                 '"storageBucket" option when initializing the App, or specify the bucket '
                 'name explicitly when calling the storage.bucket() function.')
-        if not bucket_name or not isinstance(bucket_name, six.string_types):
+        if not bucket_name or not isinstance(bucket_name, str):
             raise ValueError(
                 'Invalid storage bucket name: "{0}". Bucket name must be a non-empty '
                 'string.'.format(bucket_name))
diff --git a/integration/test_auth.py b/integration/test_auth.py
index c3759ce12..5d26dd9f1 100644
--- a/integration/test_auth.py
+++ b/integration/test_auth.py
@@ -17,13 +17,13 @@
 import datetime
 import random
 import time
+from urllib import parse
 import uuid
 
 import google.oauth2.credentials
 from google.auth import transport
 import pytest
 import requests
-import six
 
 import firebase_admin
 from firebase_admin import auth
@@ -82,8 +82,8 @@ def _sign_in_with_email_link(email, oob_code, api_key):
     return resp.json().get('idToken')
 
 def _extract_link_params(link):
-    query = six.moves.urllib.parse.urlparse(link).query
-    query_dict = dict(six.moves.urllib.parse.parse_qsl(query))
+    query = parse.urlparse(link).query
+    query_dict = dict(parse.parse_qsl(query))
     return query_dict
 
 def test_custom_token(api_key):
@@ -427,7 +427,7 @@ def test_import_users_with_password(api_key):
 
 def test_password_reset(new_user_email_unverified, api_key):
     link = auth.generate_password_reset_link(new_user_email_unverified.email)
-    assert isinstance(link, six.string_types)
+    assert isinstance(link, str)
     query_dict = _extract_link_params(link)
     user_email = _reset_password(query_dict['oobCode'], 'newPassword', api_key)
     assert new_user_email_unverified.email == user_email
@@ -436,7 +436,7 @@ def test_password_reset(new_user_email_unverified, api_key):
 
 def test_email_verification(new_user_email_unverified, api_key):
     link = auth.generate_email_verification_link(new_user_email_unverified.email)
-    assert isinstance(link, six.string_types)
+    assert isinstance(link, str)
     query_dict = _extract_link_params(link)
     user_email = _verify_email(query_dict['oobCode'], api_key)
     assert new_user_email_unverified.email == user_email
@@ -446,7 +446,7 @@ def test_password_reset_with_settings(new_user_email_unverified, api_key):
     action_code_settings = auth.ActionCodeSettings(ACTION_LINK_CONTINUE_URL)
     link = auth.generate_password_reset_link(new_user_email_unverified.email,
                                              action_code_settings=action_code_settings)
-    assert isinstance(link, six.string_types)
+    assert isinstance(link, str)
     query_dict = _extract_link_params(link)
     assert query_dict['continueUrl'] == ACTION_LINK_CONTINUE_URL
     user_email = _reset_password(query_dict['oobCode'], 'newPassword', api_key)
@@ -458,7 +458,7 @@ def test_email_verification_with_settings(new_user_email_unverified, api_key):
     action_code_settings = auth.ActionCodeSettings(ACTION_LINK_CONTINUE_URL)
     link = auth.generate_email_verification_link(new_user_email_unverified.email,
                                                  action_code_settings=action_code_settings)
-    assert isinstance(link, six.string_types)
+    assert isinstance(link, str)
     query_dict = _extract_link_params(link)
     assert query_dict['continueUrl'] == ACTION_LINK_CONTINUE_URL
     user_email = _verify_email(query_dict['oobCode'], api_key)
@@ -469,7 +469,7 @@ def test_email_sign_in_with_settings(new_user_email_unverified, api_key):
     action_code_settings = auth.ActionCodeSettings(ACTION_LINK_CONTINUE_URL)
     link = auth.generate_sign_in_with_email_link(new_user_email_unverified.email,
                                                  action_code_settings=action_code_settings)
-    assert isinstance(link, six.string_types)
+    assert isinstance(link, str)
     query_dict = _extract_link_params(link)
     assert query_dict['continueUrl'] == ACTION_LINK_CONTINUE_URL
     oob_code = query_dict['oobCode']
diff --git a/integration/test_db.py b/integration/test_db.py
index abd02660f..7a73ea3ad 100644
--- a/integration/test_db.py
+++ b/integration/test_db.py
@@ -18,7 +18,6 @@
 import os
 
 import pytest
-import six
 
 import firebase_admin
 from firebase_admin import db
@@ -113,7 +112,7 @@ def test_get_value_and_etag(self, testref, testdata):
         value, etag = testref.get(etag=True)
         assert isinstance(value, dict)
         assert testdata == value
-        assert isinstance(etag, six.string_types)
+        assert isinstance(etag, str)
 
     def test_get_shallow(self, testref):
         value = testref.get(shallow=True)
@@ -124,7 +123,7 @@ def test_get_if_changed(self, testref, testdata):
         success, data, etag = testref.get_if_changed('wrong_etag')
         assert success is True
         assert data == testdata
-        assert isinstance(etag, six.string_types)
+        assert isinstance(etag, str)
         assert testref.get_if_changed(etag) == (False, None, None)
 
     def test_get_child_value(self, testref, testdata):
@@ -211,7 +210,7 @@ def test_set_if_unchanged(self, testref):
         success, data, etag = edward.set_if_unchanged('invalid-etag', update_data)
         assert success is False
         assert data == push_data
-        assert isinstance(etag, six.string_types)
+        assert isinstance(etag, str)
 
         success, data, new_etag = edward.set_if_unchanged(etag, update_data)
         assert success is True
diff --git a/requirements.txt b/requirements.txt
index 6d28b38ac..d7fb6d736 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,4 +8,3 @@ google-api-core[grpc] >= 1.14.0, < 2.0.0dev; platform.python_implementation != '
 google-api-python-client >= 1.7.8
 google-cloud-firestore >= 1.4.0; platform.python_implementation != 'PyPy'
 google-cloud-storage >= 1.18.0
-six >= 1.6.1
diff --git a/setup.py b/setup.py
index b492ec922..43da5eb85 100644
--- a/setup.py
+++ b/setup.py
@@ -42,7 +42,6 @@
     'google-api-python-client >= 1.7.8',
     'google-cloud-firestore>=1.4.0; platform.python_implementation != "PyPy"',
     'google-cloud-storage>=1.18.0',
-    'six>=1.6.1'
 ]
 
 setup(
diff --git a/tests/test_exceptions.py b/tests/test_exceptions.py
index 3df7ec2e3..96072d91b 100644
--- a/tests/test_exceptions.py
+++ b/tests/test_exceptions.py
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import io
 import json
 import socket
 
@@ -19,7 +20,6 @@
 import pytest
 import requests
 from requests import models
-import six
 
 from googleapiclient import errors
 from firebase_admin import exceptions
@@ -174,7 +174,7 @@ def _create_response(self, status=500, payload=None):
         resp = models.Response()
         resp.status_code = status
         if payload:
-            resp.raw = six.BytesIO(payload.encode())
+            resp.raw = io.BytesIO(payload.encode())
         exc = requests.exceptions.RequestException('Test error', response=resp)
         return resp, exc
 
diff --git a/tests/test_messaging.py b/tests/test_messaging.py
index 36f5943be..33c99445b 100644
--- a/tests/test_messaging.py
+++ b/tests/test_messaging.py
@@ -17,10 +17,8 @@
 import json
 import numbers
 
-import pytest
-import six
-
 from googleapiclient.http import HttpMockSequence
+import pytest
 
 import firebase_admin
 from firebase_admin import exceptions
@@ -288,7 +286,7 @@ def test_invalid_priority(self, data):
         with pytest.raises(ValueError) as excinfo:
             check_encoding(messaging.Message(
                 topic='topic', android=messaging.AndroidConfig(priority=data)))
-        if isinstance(data, six.string_types):
+        if isinstance(data, str):
             assert str(excinfo.value) == 'AndroidConfig.priority must be "high" or "normal".'
         else:
             assert str(excinfo.value) == 'AndroidConfig.priority must be a non-empty string.'
@@ -405,7 +403,7 @@ def test_invalid_icon(self, data):
     def test_invalid_color(self, data):
         notification = messaging.AndroidNotification(color=data)
         excinfo = self._check_notification(notification)
-        if isinstance(data, six.string_types):
+        if isinstance(data, str):
             assert str(excinfo.value) == 'AndroidNotification.color must be in the form #RRGGBB.'
         else:
             assert str(excinfo.value) == 'AndroidNotification.color must be a non-empty string.'
@@ -491,7 +489,7 @@ def test_invalid_event_timestamp(self, timestamp):
     def test_invalid_priority(self, priority):
         notification = messaging.AndroidNotification(priority=priority)
         excinfo = self._check_notification(notification)
-        if isinstance(priority, six.string_types):
+        if isinstance(priority, str):
             if not priority:
                 expected = 'AndroidNotification.priority must be a non-empty string.'
             else:
@@ -505,7 +503,7 @@ def test_invalid_priority(self, priority):
     def test_invalid_visibility(self, visibility):
         notification = messaging.AndroidNotification(visibility=visibility)
         excinfo = self._check_notification(notification)
-        if isinstance(visibility, six.string_types):
+        if isinstance(visibility, str):
             if not visibility:
                 expected = 'AndroidNotification.visibility must be a non-empty string.'
             else:
@@ -679,7 +677,7 @@ def test_invalid_color(self, data):
         notification = messaging.LightSettings(color=data, light_on_duration_millis=300,
                                                light_off_duration_millis=200)
         excinfo = self._check_light_settings(notification)
-        if isinstance(data, six.string_types):
+        if isinstance(data, str):
             assert str(excinfo.value) == ('LightSettings.color must be in the form #RRGGBB or '
                                           '#RRGGBBAA.')
         else:
@@ -853,7 +851,7 @@ def test_invalid_badge(self, data):
     def test_invalid_direction(self, data):
         notification = messaging.WebpushNotification(direction=data)
         excinfo = self._check_notification(notification)
-        if isinstance(data, six.string_types):
+        if isinstance(data, str):
             assert str(excinfo.value) == ('WebpushNotification.direction must be "auto", '
                                           '"ltr" or "rtl".')
         else:
@@ -2195,7 +2193,7 @@ def _get_url(self, path):
     @pytest.mark.parametrize('tokens', [None, '', list(), dict(), tuple()])
     def test_invalid_tokens(self, tokens):
         expected = 'Tokens must be a string or a non-empty list of strings.'
-        if isinstance(tokens, six.string_types):
+        if isinstance(tokens, str):
             expected = 'Tokens must be non-empty strings.'
 
         with pytest.raises(ValueError) as excinfo:
diff --git a/tests/test_sseclient.py b/tests/test_sseclient.py
index 881ecc6b9..70edcf0d0 100644
--- a/tests/test_sseclient.py
+++ b/tests/test_sseclient.py
@@ -13,10 +13,10 @@
 # limitations under the License.
 
 """Tests for firebase_admin._sseclient."""
+import io
 import json
 
 import requests
-import six
 
 from firebase_admin import _sseclient
 from tests import testutils
@@ -31,7 +31,7 @@ def send(self, request, **kwargs):
         resp = super(MockSSEClientAdapter, self).send(request, **kwargs)
         resp.url = request.url
         resp.status_code = self.status
-        resp.raw = six.BytesIO(self.data.encode())
+        resp.raw = io.BytesIO(self.data.encode())
         resp.encoding = "utf-8"
         return resp
 
diff --git a/tests/test_token_gen.py b/tests/test_token_gen.py
index e92fd0059..439c1ba6e 100644
--- a/tests/test_token_gen.py
+++ b/tests/test_token_gen.py
@@ -26,7 +26,6 @@
 import google.oauth2.id_token
 import pytest
 from pytest_localserver import plugin
-import six
 
 import firebase_admin
 from firebase_admin import auth
@@ -68,7 +67,7 @@ def _merge_jwt_claims(defaults, overrides):
     return defaults
 
 def _verify_custom_token(custom_token, expected_claims):
-    assert isinstance(custom_token, six.binary_type)
+    assert isinstance(custom_token, bytes)
     token = google.oauth2.id_token.verify_token(
         custom_token,
         testutils.MockRequest(200, MOCK_PUBLIC_CERTS),
diff --git a/tests/test_user_mgt.py b/tests/test_user_mgt.py
index f1572baf2..9b0b4ce11 100644
--- a/tests/test_user_mgt.py
+++ b/tests/test_user_mgt.py
@@ -17,9 +17,9 @@
 import base64
 import json
 import time
+from urllib import parse
 
 import pytest
-from six.moves import urllib
 
 import firebase_admin
 from firebase_admin import auth
@@ -772,7 +772,7 @@ def _check_rpc_calls(self, recorder, expected=None):
         if expected is None:
             expected = {'maxResults' : '1000'}
         assert len(recorder) == 1
-        request = dict(urllib.parse.parse_qsl(urllib.parse.urlsplit(recorder[0].url).query))
+        request = dict(parse.parse_qsl(parse.urlsplit(recorder[0].url).query))
         assert request == expected
 
 
diff --git a/tests/testutils.py b/tests/testutils.py
index 9c69663a0..d0663ead1 100644
--- a/tests/testutils.py
+++ b/tests/testutils.py
@@ -13,13 +13,13 @@
 # limitations under the License.
 
 """Common utility classes and functions for testing."""
+import io
 import os
 
 from google.auth import credentials
 from google.auth import transport
 from requests import adapters
 from requests import models
-import six
 
 import firebase_admin
 
@@ -145,7 +145,7 @@ def send(self, request, **kwargs): # pylint: disable=arguments-differ
         resp = models.Response()
         resp.url = request.url
         resp.status_code = self._statuses[self._current_response]
-        resp.raw = six.BytesIO(self._responses[self._current_response].encode())
+        resp.raw = io.BytesIO(self._responses[self._current_response].encode())
         self._current_response = min(self._current_response + 1, len(self._responses) - 1)
         return resp