diff --git a/falcon/request.py b/falcon/request.py
index 30a2bd3..dd49159 100644
--- a/falcon/request.py
+++ b/falcon/request.py
@@ -243,6 +243,7 @@ class Request(object):
         'options',
         '_cookies',
         '_cached_access_route',
+        '__dict__',
     )
 
     # Child classes may override this
diff --git a/falcon/response.py b/falcon/response.py
index 44d3d5d..fd25479 100644
--- a/falcon/response.py
+++ b/falcon/response.py
@@ -116,6 +116,7 @@ class Response(object):
         'stream',
         'stream_len',
         'context',
+        '__dict__',
     )
 
     # Child classes may override this
diff --git a/tests/test_slots.py b/tests/test_slots.py
new file mode 100644
index 0000000..665ea32
--- /dev/null
+++ b/tests/test_slots.py
@@ -0,0 +1,22 @@
+from falcon import Request, Response
+import falcon.testing as testing
+
+
+class TestSlots(testing.TestBase):
+
+    def test_slots_request(self):
+        env = testing.create_environ()
+        req = Request(env)
+
+        try:
+            req.doesnt = 'exist'
+        except AttributeError:
+            self.fail('Unable to add additional variables dynamically')
+
+    def test_slots_response(self):
+        resp = Response()
+
+        try:
+            resp.doesnt = 'exist'
+        except AttributeError:
+            self.fail('Unable to add additional variables dynamically')