diff --git a/django/core/handlers/base.py b/django/core/handlers/base.py
index e6ef6e2f9e..f144ce4bb1 100644
--- a/django/core/handlers/base.py
+++ b/django/core/handlers/base.py
@@ -68,6 +68,9 @@ class BaseHandler(object):
         from django.core import exceptions, urlresolvers
         from django.conf import settings
 
+        # Reset the urlconf for this thread.
+        urlresolvers.set_urlconf(None)
+
         # Apply request middleware
         for middleware_method in self._request_middleware:
             response = middleware_method(request)
@@ -77,61 +80,69 @@ class BaseHandler(object):
         # Get urlconf from request object, if available.  Otherwise use default.
         urlconf = getattr(request, "urlconf", settings.ROOT_URLCONF)
 
+        # Set the urlconf for this thread to the one specified above.
+        urlresolvers.set_urlconf(urlconf)
+
         resolver = urlresolvers.RegexURLResolver(r'^/', urlconf)
         try:
-            callback, callback_args, callback_kwargs = resolver.resolve(
-                    request.path_info)
-
-            # Apply view middleware
-            for middleware_method in self._view_middleware:
-                response = middleware_method(request, callback, callback_args, callback_kwargs)
-                if response:
-                    return response
-
             try:
-                response = callback(request, *callback_args, **callback_kwargs)
-            except Exception, e:
-                # If the view raised an exception, run it through exception
-                # middleware, and if the exception middleware returns a
-                # response, use that. Otherwise, reraise the exception.
-                for middleware_method in self._exception_middleware:
-                    response = middleware_method(request, e)
+                callback, callback_args, callback_kwargs = resolver.resolve(
+                        request.path_info)
+
+                # Apply view middleware
+                for middleware_method in self._view_middleware:
+                    response = middleware_method(request, callback, callback_args, callback_kwargs)
                     if response:
                         return response
-                raise
 
-            # Complain if the view returned None (a common error).
-            if response is None:
                 try:
-                    view_name = callback.func_name # If it's a function
-                except AttributeError:
-                    view_name = callback.__class__.__name__ + '.__call__' # If it's a class
-                raise ValueError, "The view %s.%s didn't return an HttpResponse object." % (callback.__module__, view_name)
+                    response = callback(request, *callback_args, **callback_kwargs)
+                except Exception, e:
+                    # If the view raised an exception, run it through exception
+                    # middleware, and if the exception middleware returns a
+                    # response, use that. Otherwise, reraise the exception.
+                    for middleware_method in self._exception_middleware:
+                        response = middleware_method(request, e)
+                        if response:
+                            return response
+                    raise
 
-            return response
-        except http.Http404, e:
-            if settings.DEBUG:
-                from django.views import debug
-                return debug.technical_404_response(request, e)
-            else:
-                try:
-                    callback, param_dict = resolver.resolve404()
-                    return callback(request, **param_dict)
-                except:
+                # Complain if the view returned None (a common error).
+                if response is None:
                     try:
-                        return self.handle_uncaught_exception(request, resolver, sys.exc_info())
-                    finally:
-                        receivers = signals.got_request_exception.send(sender=self.__class__, request=request)
-        except exceptions.PermissionDenied:
-            return http.HttpResponseForbidden('<h1>Permission denied</h1>')
-        except SystemExit:
-            # Allow sys.exit() to actually exit. See tickets #1023 and #4701
-            raise
-        except: # Handle everything else, including SuspiciousOperation, etc.
-            # Get the exception info now, in case another exception is thrown later.
-            exc_info = sys.exc_info()
-            receivers = signals.got_request_exception.send(sender=self.__class__, request=request)
-            return self.handle_uncaught_exception(request, resolver, exc_info)
+                        view_name = callback.func_name # If it's a function
+                    except AttributeError:
+                        view_name = callback.__class__.__name__ + '.__call__' # If it's a class
+                    raise ValueError, "The view %s.%s didn't return an HttpResponse object." % (callback.__module__, view_name)
+
+                return response
+            except http.Http404, e:
+                if settings.DEBUG:
+                    from django.views import debug
+                    return debug.technical_404_response(request, e)
+                else:
+                    try:
+                        callback, param_dict = resolver.resolve404()
+                        return callback(request, **param_dict)
+                    except:
+                        try:
+                            return self.handle_uncaught_exception(request, resolver, sys.exc_info())
+                        finally:
+                            receivers = signals.got_request_exception.send(sender=self.__class__, request=request)
+            except exceptions.PermissionDenied:
+                return http.HttpResponseForbidden('<h1>Permission denied</h1>')
+            except SystemExit:
+                # Allow sys.exit() to actually exit. See tickets #1023 and #4701
+                raise
+            except: # Handle everything else, including SuspiciousOperation, etc.
+                # Get the exception info now, in case another exception is thrown later.
+                exc_info = sys.exc_info()
+                receivers = signals.got_request_exception.send(sender=self.__class__, request=request)
+                return self.handle_uncaught_exception(request, resolver, exc_info)
+        finally:
+            # Reset URLconf for this thread on the way out for complete
+            # isolation of request.urlconf
+            urlresolvers.set_urlconf(None)
 
     def handle_uncaught_exception(self, request, resolver, exc_info):
         """
diff --git a/django/core/urlresolvers.py b/django/core/urlresolvers.py
index eedb8f126c..a924afeaf8 100644
--- a/django/core/urlresolvers.py
+++ b/django/core/urlresolvers.py
@@ -10,6 +10,7 @@ a string) and returns a tuple in this format:
 import re
 
 from django.http import Http404
+from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured, ViewDoesNotExist
 from django.utils.datastructures import MultiValueDict
 from django.utils.encoding import iri_to_uri, force_unicode, smart_str
@@ -32,6 +33,9 @@ _callable_cache = {} # Maps view and url pattern names to their view functions.
 # be empty.
 _prefixes = {}
 
+# Overridden URLconfs for each thread are stored here.
+_urlconfs = {}
+
 class Resolver404(Http404):
     pass
 
@@ -300,9 +304,13 @@ class RegexURLResolver(object):
                 "arguments '%s' not found." % (lookup_view_s, args, kwargs))
 
 def resolve(path, urlconf=None):
+    if urlconf is None:
+        urlconf = get_urlconf()
     return get_resolver(urlconf).resolve(path)
 
 def reverse(viewname, urlconf=None, args=None, kwargs=None, prefix=None, current_app=None):
+    if urlconf is None:
+        urlconf = get_urlconf()
     resolver = get_resolver(urlconf)
     args = args or []
     kwargs = kwargs or {}
@@ -371,3 +379,25 @@ def get_script_prefix():
     """
     return _prefixes.get(currentThread(), u'/')
 
+def set_urlconf(urlconf_name):
+    """
+    Sets the URLconf for the current thread (overriding the default one in
+    settings). Set to None to revert back to the default.
+    """
+    thread = currentThread()
+    if urlconf_name:
+        _urlconfs[thread] = urlconf_name
+    else:
+        # faster than wrapping in a try/except
+        if thread in _urlconfs:
+            del _urlconfs[thread]
+
+def get_urlconf(default=None):
+    """
+    Returns the root URLconf to use for the current thread if it has been
+    changed from the default one.
+    """
+    thread = currentThread()
+    if thread in _urlconfs:
+        return _urlconfs[thread]
+    return default
diff --git a/docs/topics/http/urls.txt b/docs/topics/http/urls.txt
index 0b2257cefe..fd45e79876 100644
--- a/docs/topics/http/urls.txt
+++ b/docs/topics/http/urls.txt
@@ -40,7 +40,8 @@ algorithm the system follows to determine which Python code to execute:
 
     1. Django determines the root URLconf module to use. Ordinarily,
        this is the value of the ``ROOT_URLCONF`` setting, but if the incoming
-       ``HttpRequest`` object has an attribute called ``urlconf``, its value
+       ``HttpRequest`` object has an attribute called ``urlconf`` (set by
+       middleware :ref:`request processing <request-middleware>`), its value
        will be used in place of the ``ROOT_URLCONF`` setting.
 
     2. Django loads that Python module and looks for the variable
diff --git a/tests/regressiontests/urlpatterns_reverse/middleware.py b/tests/regressiontests/urlpatterns_reverse/middleware.py
new file mode 100644
index 0000000000..7bb9aa924f
--- /dev/null
+++ b/tests/regressiontests/urlpatterns_reverse/middleware.py
@@ -0,0 +1,7 @@
+from django.core.urlresolvers import set_urlconf
+
+import urlconf_inner
+
+class ChangeURLconfMiddleware(object):
+    def process_request(self, request):
+        request.urlconf = urlconf_inner.__name__
diff --git a/tests/regressiontests/urlpatterns_reverse/tests.py b/tests/regressiontests/urlpatterns_reverse/tests.py
index d4f281ba81..34c9db25d3 100644
--- a/tests/regressiontests/urlpatterns_reverse/tests.py
+++ b/tests/regressiontests/urlpatterns_reverse/tests.py
@@ -16,11 +16,16 @@ ImproperlyConfigured: The included urlconf regressiontests.urlpatterns_reverse.n
 
 import unittest
 
+from django.conf import settings
 from django.core.urlresolvers import reverse, resolve, NoReverseMatch, Resolver404
 from django.http import HttpResponseRedirect, HttpResponsePermanentRedirect
 from django.shortcuts import redirect
 from django.test import TestCase
 
+import urlconf_outer
+import urlconf_inner
+import middleware
+
 test_data = (
     ('places', '/places/3/', [3], {}),
     ('places', '/places/3/', ['3'], {}),
@@ -239,3 +244,35 @@ class NamespaceTests(TestCase):
         self.assertEquals('/other1/inner/37/42/', reverse('nodefault:urlobject-view', args=[37,42], current_app='other-ns1'))
         self.assertEquals('/other1/inner/42/37/', reverse('nodefault:urlobject-view', kwargs={'arg1':42, 'arg2':37}, current_app='other-ns1'))
 
+
+class RequestURLconfTests(TestCase):
+    def setUp(self):
+        self.root_urlconf = settings.ROOT_URLCONF
+        self.middleware_classes = settings.MIDDLEWARE_CLASSES
+        settings.ROOT_URLCONF = urlconf_outer.__name__
+
+    def tearDown(self):
+        settings.ROOT_URLCONF = self.root_urlconf
+        settings.MIDDLEWARE_CLASSES = self.middleware_classes
+
+    def test_urlconf(self):
+        response = self.client.get('/test/me/')
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response.content, 'outer:/test/me/,'
+                                           'inner:/inner_urlconf/second_test/')
+        response = self.client.get('/inner_urlconf/second_test/')
+        self.assertEqual(response.status_code, 200)
+        response = self.client.get('/second_test/')
+        self.assertEqual(response.status_code, 404)
+
+    def test_urlconf_overridden(self):
+        settings.MIDDLEWARE_CLASSES += (
+            '%s.ChangeURLconfMiddleware' % middleware.__name__,
+        )
+        response = self.client.get('/test/me/')
+        self.assertEqual(response.status_code, 404)
+        response = self.client.get('/inner_urlconf/second_test/')
+        self.assertEqual(response.status_code, 404)
+        response = self.client.get('/second_test/')
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response.content, 'outer:,inner:/second_test/')
diff --git a/tests/regressiontests/urlpatterns_reverse/urlconf_inner.py b/tests/regressiontests/urlpatterns_reverse/urlconf_inner.py
new file mode 100644
index 0000000000..d188e06421
--- /dev/null
+++ b/tests/regressiontests/urlpatterns_reverse/urlconf_inner.py
@@ -0,0 +1,12 @@
+from django.conf.urls.defaults import *
+from django.template import Template, Context
+from django.http import HttpResponse
+
+def inner_view(request):
+    content = Template('{% url outer as outer_url %}outer:{{ outer_url }},'
+                       '{% url inner as inner_url %}inner:{{ inner_url }}').render(Context())
+    return HttpResponse(content)
+
+urlpatterns = patterns('',
+    url(r'^second_test/$', inner_view, name='inner'),
+)
\ No newline at end of file
diff --git a/tests/regressiontests/urlpatterns_reverse/urlconf_outer.py b/tests/regressiontests/urlpatterns_reverse/urlconf_outer.py
new file mode 100644
index 0000000000..506e03666e
--- /dev/null
+++ b/tests/regressiontests/urlpatterns_reverse/urlconf_outer.py
@@ -0,0 +1,9 @@
+from django.conf.urls.defaults import *
+
+import urlconf_inner
+
+
+urlpatterns = patterns('',
+    url(r'^test/me/$', urlconf_inner.inner_view, name='outer'),
+    url(r'^inner_urlconf/', include(urlconf_inner.__name__))
+)
\ No newline at end of file