diff --git a/stack.yaml b/stack.yaml
index 213e9db3..b53c2b2e 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -13,3 +13,5 @@ packages:
   - ./yesod
   - ./yesod-eventsource
   - ./yesod-websockets
+extra-deps:
+- unliftio-core-0.1.0.0
diff --git a/yesod-core/Yesod/Core/Types.hs b/yesod-core/Yesod/Core/Types.hs
index 607dde01..fd4572de 100644
--- a/yesod-core/Yesod/Core/Types.hs
+++ b/yesod-core/Yesod/Core/Types.hs
@@ -66,6 +66,7 @@ import Data.Conduit.Lazy (MonadActive, monadActive)
 import Yesod.Core.TypeCache (TypeMap, KeyedTypeMap)
 import Control.Monad.Logger (MonadLoggerIO (..))
 import Data.Semigroup (Semigroup)
+import Control.Monad.IO.Unlift (MonadUnliftIO (..), UnliftIO (..), withUnliftIO)
 
 -- Sessions
 type SessionMap = Map Text ByteString
@@ -424,6 +425,12 @@ instance MonadBaseControl b m => MonadBaseControl b (WidgetT site m) where
         liftBaseWith $ \runInBase ->
             f $ runInBase . (\(WidgetT w) -> w ref reader')
     restoreM = WidgetT . const . const . restoreM
+-- | @since 1.4.38
+instance MonadUnliftIO m => MonadUnliftIO (WidgetT site m) where
+  {-# INLINE askUnliftIO #-}
+  askUnliftIO = WidgetT $ \ref r ->
+                withUnliftIO $ \u ->
+                return (UnliftIO (\(WidgetT w) -> unliftIO u $ w ref r))
 instance Monad m => MonadReader site (WidgetT site m) where
     ask = WidgetT $ \_ hd -> return (rheSite $ handlerEnv hd)
     local f (WidgetT g) = WidgetT $ \ref hd -> g ref hd
@@ -511,6 +518,12 @@ instance MonadBaseControl b m => MonadBaseControl b (HandlerT site m) where
         liftBaseWith $ \runInBase ->
             f $ runInBase . (\(HandlerT r) -> r reader')
     restoreM = HandlerT . const . restoreM
+-- | @since 1.4.38
+instance MonadUnliftIO m => MonadUnliftIO (HandlerT site m) where
+  {-# INLINE askUnliftIO #-}
+  askUnliftIO = HandlerT $ \r ->
+                withUnliftIO $ \u ->
+                return (UnliftIO (unliftIO u . flip unHandlerT r))
 
 instance MonadThrow m => MonadThrow (HandlerT site m) where
     throwM = lift . monadThrow
diff --git a/yesod-core/yesod-core.cabal b/yesod-core/yesod-core.cabal
index 3dc85c18..84ae5ab0 100644
--- a/yesod-core/yesod-core.cabal
+++ b/yesod-core/yesod-core.cabal
@@ -70,6 +70,7 @@ library
                    , auto-update
                    , semigroups
                    , byteable
+                   , unliftio-core
 
     exposed-modules: Yesod.Core
                      Yesod.Core.Content