diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py
index ba707d4140..d425c8b32b 100644
--- a/django/db/models/sql/compiler.py
+++ b/django/db/models/sql/compiler.py
@@ -330,7 +330,7 @@ class SQLCompiler(object):
                 continue
             col, order = get_order_dir(field, asc)
             if col in self.query.aggregate_select:
-                result.append('%s %s' % (col, order))
+                result.append('%s %s' % (qn(col), order))
                 continue
             if '.' in field:
                 # This came in through an extra(order_by=...) addition. Pass it
diff --git a/tests/regressiontests/aggregation_regress/tests.py b/tests/regressiontests/aggregation_regress/tests.py
index ad79923a8a..67220b7c77 100644
--- a/tests/regressiontests/aggregation_regress/tests.py
+++ b/tests/regressiontests/aggregation_regress/tests.py
@@ -747,6 +747,19 @@ class AggregationTests(TestCase):
             attrgetter("name")
         )
 
+    def test_quoting_aggregate_order_by(self):
+        qs = Book.objects.filter(
+            name="Python Web Development with Django"
+        ).annotate(
+            authorCount=Count("authors")
+        ).order_by("authorCount")
+        self.assertQuerysetEqual(
+            qs, [
+                ("Python Web Development with Django", 3),
+            ],
+            lambda b: (b.name, b.authorCount)
+        )
+
     @skipUnlessDBFeature('supports_stddev')
     def test_stddev(self):
         self.assertEqual(