diff --git a/django/db/transaction.py b/django/db/transaction.py
index e392c13b32..b83aaa6440 100644
--- a/django/db/transaction.py
+++ b/django/db/transaction.py
@@ -1,7 +1,8 @@
+from contextlib import ContextDecorator
+
 from django.db import (
     DEFAULT_DB_ALIAS, DatabaseError, Error, ProgrammingError, connections,
 )
-from django.utils.decorators import ContextDecorator
 
 
 class TransactionManagementError(ProgrammingError):
diff --git a/django/utils/decorators.py b/django/utils/decorators.py
index 3b2a002e7b..a3af946b33 100644
--- a/django/utils/decorators.py
+++ b/django/utils/decorators.py
@@ -1,10 +1,7 @@
 "Functions that help with dynamically creating decorators for views."
 
-try:
-    from contextlib import ContextDecorator
-except ImportError:
-    ContextDecorator = None
-
+# For backwards compatibility in Django 2.0.
+from contextlib import ContextDecorator  # noqa
 from functools import WRAPPER_ASSIGNMENTS, update_wrapper, wraps
 
 
@@ -166,21 +163,6 @@ def make_middleware_decorator(middleware_class):
     return _make_decorator
 
 
-if ContextDecorator is None:
-    # ContextDecorator was introduced in Python 3.2
-    # See https://docs.python.org/3/library/contextlib.html#contextlib.ContextDecorator
-    class ContextDecorator:
-        """
-        A base class that enables a context manager to also be used as a decorator.
-        """
-        def __call__(self, func):
-            @wraps(func, assigned=available_attrs(func))
-            def inner(*args, **kwargs):
-                with self:
-                    return func(*args, **kwargs)
-            return inner
-
-
 class classproperty:
     def __init__(self, method=None):
         self.fget = method
diff --git a/django/utils/timezone.py b/django/utils/timezone.py
index 66bfa00030..bc6d60e228 100644
--- a/django/utils/timezone.py
+++ b/django/utils/timezone.py
@@ -3,13 +3,13 @@ Timezone-related classes and functions.
 """
 
 import functools
+from contextlib import ContextDecorator
 from datetime import datetime, timedelta, tzinfo
 from threading import local
 
 import pytz
 
 from django.conf import settings
-from django.utils.decorators import ContextDecorator
 
 __all__ = [
     'utc', 'get_fixed_timezone',
diff --git a/django/utils/translation/__init__.py b/django/utils/translation/__init__.py
index a8f3b751b4..2c508572b8 100644
--- a/django/utils/translation/__init__.py
+++ b/django/utils/translation/__init__.py
@@ -3,8 +3,8 @@ Internationalization support.
 """
 import re
 import warnings
+from contextlib import ContextDecorator
 
-from django.utils.decorators import ContextDecorator
 from django.utils.deprecation import RemovedInDjango21Warning
 from django.utils.encoding import force_text
 from django.utils.functional import lazy