diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
index 18b7dc3668ceee8069b2a61349cba4b91d96f6df..906560bd44c82eea1fec8b15001a4e9b72c588dc 100644
--- a/activerecord/lib/active_record/associations/collection_association.rb
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -34,7 +34,7 @@ def reader(force_reload = false)
           reload
         end
 
-        CollectionProxy.new(klass, self)
+        @proxy ||= CollectionProxy.new(klass, self)
       end
 
       # Implements the writer method, e.g. foo.items= for Foo.has_many :items
diff --git a/activerecord/test/cases/associations_test.rb b/activerecord/test/cases/associations_test.rb
index 41529cd050e190f395a33cb9289909f005d34db4..a06bacafca7b758b61f70ced319a16ad950903d7 100644
--- a/activerecord/test/cases/associations_test.rb
+++ b/activerecord/test/cases/associations_test.rb
@@ -237,6 +237,11 @@ def test_scoped_allows_conditions
     assert david.projects.scope.is_a?(ActiveRecord::Relation)
     assert_equal david.projects, david.projects.scope
   end
+
+  test "proxy object is cached" do
+    david = developers(:david)
+    assert david.projects.equal?(david.projects)
+  end
 end
 
 class OverridingAssociationsTest < ActiveRecord::TestCase