diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -2,6 +2,6 @@
 
 [![CircleCI](https://circleci.com/gh/ejconlon/little-rio/tree/master.svg?style=svg)](https://circleci.com/gh/ejconlon/little-rio/tree/master)
 
-When you need just the `RIO` monad (but you want a `MonadCatch` instance)
+When you need just the `RIO` monad (but you want a `MonadCatch` instance and some other orphans)
 
-This is derived from the RIO library ([LICENSE](https://hackage.haskell.org/package/rio-0.1.14.0/src/LICENSE)).
+This is derived from the `rio` library ([LICENSE](https://hackage.haskell.org/package/rio-0.1.18.0/src/LICENSE)) and the `rio-orphans` library ([LICENSE](https://hackage.haskell.org/package/rio-orphans-0.1.1.0/src/LICENSE))
diff --git a/little-rio.cabal b/little-rio.cabal
--- a/little-rio.cabal
+++ b/little-rio.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 164d0fdd886b3210c590587e48d1ccd93c6aa132cf9f4e0ff385825b9c30392b
+-- hash: d22342ec62f05927c43b7ecfdacef567fa519fafdf63e0545b49683ac1a14856
 
 name:           little-rio
-version:        0.1.1
+version:        0.2.0
 synopsis:       When you need just the RIO monad
 description:    Please see the README on GitHub at <https://github.com/ejconlon/little-rio#readme>
 category:       Control
@@ -36,9 +36,11 @@
   ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wpartial-fields -Wredundant-constraints -fno-warn-unused-top-binds
   build-depends:
       base >=4.12 && <5
-    , exceptions >=0.10
-    , microlens >=0.4
-    , microlens-mtl >=0.2
-    , mtl >=2.2
-    , unliftio-core >=0.1
+    , exceptions >=0.10 && <1
+    , microlens >=0.4 && <1
+    , microlens-mtl >=0.2 && <1
+    , mtl >=2.2 && <3
+    , primitive >=0.7.0.1 && <1
+    , resourcet >=1.2.4.2 && <2
+    , unliftio-core >=0.1 && <1
   default-language: Haskell2010
diff --git a/src/LittleRIO.hs b/src/LittleRIO.hs
--- a/src/LittleRIO.hs
+++ b/src/LittleRIO.hs
@@ -1,16 +1,20 @@
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE FunctionalDependencies #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE UndecidableInstances #-}
 
 {- |
-Most definitions follow the RIO lib: https://hackage.haskell.org/package/rio-0.1.14.0/docs/RIO.html
+Most definitions follow the RIO lib: https://hackage.haskell.org/package/rio-0.1.18.0/docs/RIO.html
+The rest follow from orphans: https://hackage.haskell.org/package/rio-orphans-0.1.1.0/docs/src/RIO.Orphans.html
 See LICENSE info in the README.
 -}
 module LittleRIO
-  ( HasStateRef (..)
+  ( HasResourceMap (..)
+  , HasStateRef (..)
   , HasWriteRef (..)
   , SomeRef (..)
+  , ResourceMap
   , RIO (..)
   , getStateRef
   , liftRIO
@@ -23,17 +27,22 @@
   , putStateRef
   , runRIO
   , readSomeRef
+  , resourceRIO
   , tellWriteRef
   , unliftRIO
+  , withResourceMap
   , writeSomeRef
   ) where
 
 import Control.Applicative (liftA2)
 import Control.Monad.Catch (MonadCatch, MonadMask, MonadThrow)
 import Control.Monad.IO.Class (MonadIO (..))
-import Control.Monad.IO.Unlift (MonadUnliftIO, UnliftIO, askUnliftIO)
+import Control.Monad.IO.Unlift (MonadUnliftIO (..), UnliftIO, askUnliftIO)
+import Control.Monad.Primitive (PrimMonad (..))
 import Control.Monad.Reader (MonadReader (..), ReaderT (..))
 import Control.Monad.State (MonadState (..))
+import Control.Monad.Trans.Resource (runResourceT)
+import Control.Monad.Trans.Resource.Internal (MonadResource (..), ReleaseMap, ResourceT (..))
 import Control.Monad.Writer (MonadWriter (..))
 import Data.IORef (IORef, newIORef, readIORef, writeIORef)
 import Lens.Micro (Lens')
@@ -50,6 +59,10 @@
   mempty = pure mempty
   mappend = (<>)
 
+instance PrimMonad (RIO env) where
+  type PrimState (RIO env) = PrimState IO
+  primitive = RIO . ReaderT . const . primitive
+
 mapRIO :: (env -> env') -> RIO env' a -> RIO env a
 mapRIO f m = do
   env <- ask
@@ -76,7 +89,7 @@
 writeSomeRef (SomeRef _ x) = liftIO . x
 
 modifySomeRef :: MonadIO m => SomeRef a -> (a -> a) -> m ()
-modifySomeRef (SomeRef read' write) f = liftIO (fmap f read' >>= write)
+modifySomeRef (SomeRef read' write) f = liftIO (read' >>= write . f)
 
 ioRefToSomeRef :: IORef a -> SomeRef a
 ioRefToSomeRef ref = SomeRef (readIORef ref) (writeIORef ref)
@@ -142,3 +155,21 @@
   tell = tellWriteRef
   listen = listenWriteRef
   pass = passWriteRef
+
+type ResourceMap = IORef ReleaseMap
+
+withResourceMap :: MonadUnliftIO m => (ResourceMap -> m a) -> m a
+withResourceMap inner =
+  withRunInIO (\run -> runResourceT (ResourceT (run . inner)))
+
+class HasResourceMap env where
+  resourceMapL :: Lens' env ResourceMap
+
+instance HasResourceMap (IORef ReleaseMap) where
+  resourceMapL = id
+
+resourceRIO :: HasResourceMap env => ResourceT IO a -> RIO env a
+resourceRIO (ResourceT f) = view resourceMapL >>= liftIO . f
+
+instance HasResourceMap env => MonadResource (RIO env) where
+  liftResourceT = resourceRIO