diff --git a/.travis.yml b/.travis.yml
index 78118db..78ac7e2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,6 +9,7 @@ env:
   - DJANGO=django==1.5
   - DJANGO=django==1.6
   - DJANGO=django==1.7
+  - DJANGO=https://www.djangoproject.com/download/1.8a1/tarball/
   #- DJANGO=https://github.com/django/django/archive/stable/1.6.x.zip
 
 matrix:
@@ -19,6 +20,8 @@ matrix:
     env: DJANGO=django==1.4.5
   - python: "2.6"
     env: DJANGO=django==1.7
+  - python: "2.6"
+    env: DJANGO=https://www.djangoproject.com/download/1.8a1/tarball/
 
 install:
   - pip install $DJANGO coverage==3.6
diff --git a/polymorphic/query.py b/polymorphic/query.py
index 35d091a..eab634e 100644
--- a/polymorphic/query.py
+++ b/polymorphic/query.py
@@ -6,6 +6,7 @@ from __future__ import absolute_import
 
 from collections import defaultdict
 
+import django
 from django.db.models.query import QuerySet
 from django.contrib.contenttypes.models import ContentType
 from django.utils import six
@@ -95,10 +96,22 @@ class PolymorphicQuerySet(QuerySet):
     def _process_aggregate_args(self, args, kwargs):
         """for aggregate and annotate kwargs: allow ModelX___field syntax for kwargs, forbid it for args.
         Modifies kwargs if needed (these are Aggregate objects, we translate the lookup member variable)"""
+
+        def patch_lookup(a):
+            if django.VERSION < (1, 8):
+                a.lookup = translate_polymorphic_field_path(self.model, a.lookup)
+            else:
+                # With Django > 1.8, the field on which the aggregate operates is
+                # stored inside a query expression.
+                a.source_expressions[0].name = translate_polymorphic_field_path(
+                    self.model, a.source_expressions[0].name)
+
+        get_lookup = lambda a: a.lookup if django.VERSION < (1, 8) else a.source_expressions[0].name
+
         for a in args:
-            assert not '___' in a.lookup, 'PolymorphicModel: annotate()/aggregate(): ___ model lookup supported for keyword arguments only'
+            assert '___' not in get_lookup(a), 'PolymorphicModel: annotate()/aggregate(): ___ model lookup supported for keyword arguments only'
         for a in six.itervalues(kwargs):
-            a.lookup = translate_polymorphic_field_path(self.model, a.lookup)
+            patch_lookup(a)
 
     def annotate(self, *args, **kwargs):
         """translate the polymorphic field paths in the kwargs, then call vanilla annotate.
diff --git a/polymorphic/query_translate.py b/polymorphic/query_translate.py
index b6ee8cc..4008e61 100644
--- a/polymorphic/query_translate.py
+++ b/polymorphic/query_translate.py
@@ -7,7 +7,15 @@ from __future__ import absolute_import
 from django.db import models
 from django.contrib.contenttypes.models import ContentType
 from django.db.models import Q, FieldDoesNotExist
-from django.db.models.related import RelatedObject
+
+try:
+    from django.db.models.related import RelatedObject
+except ImportError:
+    # django.db.models.related.RelatedObject was replaced
+    # by django.db.models.fields.related.ForeignObjectRel in
+    # Django 1.8
+    from django.db.models.fields.related import ForeignObjectRel
+    RelatedObject = ForeignObjectRel
 
 from functools import reduce
 
diff --git a/tox.ini b/tox.ini
index a642ae1..dc4c278 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,14 +8,17 @@ envlist=
     py27-django15,
     py27-django16,
     py27-django17,
+    py27-django18,
 
     py32-django15,
     py32-django16,
     py32-django17,
+    py32-django18,
 
     py33-django15,
     py33-django16,
     py33-django17,
+    py33-django18,
 
     py33-django-dev,
     docs,
@@ -61,6 +64,11 @@ basepython=python2.7
 deps=
     django==1.7
 
+[testenv:py27-django18]
+basepython=python2.7
+deps=
+    https://www.djangoproject.com/download/1.8a1/tarball/
+
 [testenv:py32-django15]
 basepython=python3.2
 deps=
@@ -76,6 +84,11 @@ basepython=python3.2
 deps=
     django==1.7
 
+[testenv:py32-django18]
+basepython=python3.2
+deps=
+    https://www.djangoproject.com/download/1.8a1/tarball/
+
 [testenv:py33-django15]
 basepython=python3.3
 deps=
@@ -91,6 +104,11 @@ basepython=python3.3
 deps=
     django==1.7
 
+[testenv:py33-django18]
+basepython=python3.3
+deps=
+    https://www.djangoproject.com/download/1.8a1/tarball/
+
 [testenv:py33-django-dev]
 basepython=python3.3
 deps=