diff --git a/fb.cabal b/fb.cabal
--- a/fb.cabal
+++ b/fb.cabal
@@ -1,5 +1,5 @@
 name:              fb
-version:           0.11.1
+version:           0.11.2
 license:           BSD3
 license-file:      LICENSE
 author:            Felipe Lessa
diff --git a/src/Facebook.hs b/src/Facebook.hs
--- a/src/Facebook.hs
+++ b/src/Facebook.hs
@@ -3,6 +3,7 @@
       FacebookT
     , runFacebookT
     , runNoAuthFacebookT
+    , mapFacebookT
     , beta_runFacebookT
     , beta_runNoAuthFacebookT
     , Auth
diff --git a/src/Facebook/Monad.hs b/src/Facebook/Monad.hs
--- a/src/Facebook/Monad.hs
+++ b/src/Facebook/Monad.hs
@@ -13,6 +13,7 @@
     , getTier
     , withTier
     , runResourceInFb
+    , mapFacebookT
 
       -- * Re-export
     , lift
@@ -27,7 +28,7 @@
 import Control.Monad.Trans.Control ( MonadTransControl(..), MonadBaseControl(..)
                                    , ComposeSt, defaultLiftBaseWith
                                    , defaultRestoreM )
-import Control.Monad.Trans.Reader (ReaderT(..), ask)
+import Control.Monad.Trans.Reader (ReaderT(..), ask, mapReaderT)
 import Data.Typeable (Typeable)
 
 import qualified Data.Conduit as C
@@ -131,3 +132,8 @@
                    FacebookT anyAuth (C.ResourceT m) a
                 -> FacebookT anyAuth m a
 runResourceInFb (F inner) = F $ ask >>= lift . C.runResourceT . runReaderT inner
+
+
+-- | Transform the computation inside a 'FacebookT'.
+mapFacebookT :: (m a -> n b) -> FacebookT anyAuth m a -> FacebookT anyAuth n b
+mapFacebookT f = F . mapReaderT f . unF