diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,3 +1,8 @@
+0.4.1.0
+=======
+* Add Katip instances for Strict StateT, WriterT, RWST.
+* Add Katip instances for Lazy RWST.
+
 0.4.0.0
 =======
 * Drop unsafe _ioLogEnv for safe ioLogEnv
diff --git a/katip.cabal b/katip.cabal
--- a/katip.cabal
+++ b/katip.cabal
@@ -1,5 +1,5 @@
 name:                katip
-version:             0.4.0.0
+version:             0.4.1.0
 synopsis:            A structured logging framework.
 description:
   Katip is a structured logging framework. See README.md for more details.
diff --git a/src/Katip/Core.hs b/src/Katip/Core.hs
--- a/src/Katip/Core.hs
+++ b/src/Katip/Core.hs
@@ -35,8 +35,12 @@
 import           Control.Monad.Trans.Maybe
 import           Control.Monad.Trans.Reader
 import           Control.Monad.Trans.Resource
-import           Control.Monad.Trans.State
-import           Control.Monad.Trans.Writer
+import           Control.Monad.Trans.State.Lazy (StateT)
+import qualified Control.Monad.Trans.State.Strict as Strict (StateT)
+import           Control.Monad.Trans.Writer.Lazy (WriterT)
+import qualified Control.Monad.Trans.Writer.Strict as Strict (WriterT)
+import           Control.Monad.Trans.RWS.Lazy (RWST)
+import qualified Control.Monad.Trans.RWS.Strict as Strict (RWST)
 import           Data.Aeson                   (FromJSON (..), ToJSON (..),
                                                object)
 import qualified Data.Aeson                   as A
@@ -623,12 +627,22 @@
 instance Katip m => Katip (MaybeT m) where
     getLogEnv = lift getLogEnv
 
-
 instance Katip m => Katip (StateT s m) where
     getLogEnv = lift getLogEnv
 
+instance (Katip m, Monoid w) => Katip (RWST r w s m) where
+    getLogEnv = lift getLogEnv
 
+instance (Katip m, Monoid w) => Katip (Strict.RWST r w s m) where
+    getLogEnv = lift getLogEnv
+
+instance Katip m => Katip (Strict.StateT s m) where
+    getLogEnv = lift getLogEnv
+
 instance (Katip m, Monoid s) => Katip (WriterT s m) where
+    getLogEnv = lift getLogEnv
+
+instance (Katip m, Monoid s) => Katip (Strict.WriterT s m) where
     getLogEnv = lift getLogEnv
 
 instance (Katip m) => Katip (ResourceT m) where