diff --git a/src/Data/Url.hs b/src/Data/Url.hs
--- a/src/Data/Url.hs
+++ b/src/Data/Url.hs
@@ -1,11 +1,12 @@
 {-# LANGUAGE
-    KindSignatures
+    TypeFamilies
+  , DeriveFunctor
+  , KindSignatures
+  , FlexibleInstances
+  , TypeSynonymInstances
+  , UndecidableInstances
   , MultiParamTypeClasses
   , FunctionalDependencies
-  , TypeFamilies
-  , TypeSynonymInstances
-  , FlexibleInstances
-  , DeriveFunctor
   #-}
 
 module Data.Url where
@@ -14,6 +15,9 @@
 
 import Data.Functor.Identity
 import Control.Monad.Trans
+import Control.Monad.Reader
+import Control.Monad.Writer
+import Control.Monad.State
 
 
 -- * Classes
@@ -111,7 +115,26 @@
   type RunUrlReader (RelativeUrlT m) = m
   runUrlReader = runRelativeUrlT
 
+instance ( MonadReader r m
+         ) => MonadReader r (RelativeUrlT m) where
+  ask       = lift ask
+  local f (RelativeUrlT x) = RelativeUrlT $ \r ->
+    local f (x r)
 
+instance ( MonadWriter w m
+         ) => MonadWriter w (RelativeUrlT m) where
+  tell w = lift (tell w)
+  listen (RelativeUrlT x) = RelativeUrlT $ \r ->
+    listen (x r)
+  pass (RelativeUrlT x) = RelativeUrlT $ \r ->
+    pass (x r)
+
+instance ( MonadState s m
+         ) => MonadState s (RelativeUrlT m) where
+  get   = lift get
+  put x = lift (put x)
+
+
 -- ** Grounded Urls
 
 newtype GroundedUrlT m a = GroundedUrlT
@@ -146,7 +169,26 @@
   type RunUrlReader (GroundedUrlT m) = m
   runUrlReader = runGroundedUrlT
 
+instance ( MonadReader r m
+         ) => MonadReader r (GroundedUrlT m) where
+  ask       = lift ask
+  local f (GroundedUrlT x) = GroundedUrlT $ \r ->
+    local f (x r)
 
+instance ( MonadWriter w m
+         ) => MonadWriter w (GroundedUrlT m) where
+  tell w = lift (tell w)
+  listen (GroundedUrlT x) = GroundedUrlT $ \r ->
+    listen (x r)
+  pass (GroundedUrlT x) = GroundedUrlT $ \r ->
+    pass (x r)
+
+instance ( MonadState s m
+         ) => MonadState s (GroundedUrlT m) where
+  get   = lift get
+  put x = lift (put x)
+
+
 -- ** Absolute Urls
 
 newtype AbsoluteUrlT m a = AbsoluteUrlT
@@ -180,3 +222,22 @@
 instance UrlReader (AbsoluteUrlT m) where
   type RunUrlReader (AbsoluteUrlT m) = m
   runUrlReader = runAbsoluteUrlT
+
+instance ( MonadReader r m
+         ) => MonadReader r (AbsoluteUrlT m) where
+  ask       = lift ask
+  local f (AbsoluteUrlT x) = AbsoluteUrlT $ \r ->
+    local f (x r)
+
+instance ( MonadWriter w m
+         ) => MonadWriter w (AbsoluteUrlT m) where
+  tell w = lift (tell w)
+  listen (AbsoluteUrlT x) = AbsoluteUrlT $ \r ->
+    listen (x r)
+  pass (AbsoluteUrlT x) = AbsoluteUrlT $ \r ->
+    pass (x r)
+
+instance ( MonadState s m
+         ) => MonadState s (AbsoluteUrlT m) where
+  get   = lift get
+  put x = lift (put x)
diff --git a/urlpath.cabal b/urlpath.cabal
--- a/urlpath.cabal
+++ b/urlpath.cabal
@@ -1,5 +1,5 @@
 Name:                   urlpath
-Version:                3.1.1
+Version:                3.2.0
 Author:                 Athan Clark <athan.clark@gmail.com>
 Maintainer:             Athan Clark <athan.clark@gmail.com>
 License:                MIT