diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Revision history for parametric-functor
 
+## 0.1.1.0 -- 2024-01-15
+
+* Add `ParametricMonadTrans`
+
 ## 0.1.0.0 -- 2024-01-13
 
 * Initial (and hopefully final) release
diff --git a/parametric-functor.cabal b/parametric-functor.cabal
--- a/parametric-functor.cabal
+++ b/parametric-functor.cabal
@@ -1,6 +1,6 @@
 cabal-version:   3.0
 name:            parametric-functor
-version:         0.1.0.0
+version:         0.1.1.0
 synopsis:        A known-parametric Functor typeclass
 description:
   As Oleg Grenrus [argued](http://oleg.fi/gists/posts/2019-07-31-fmap-coerce-coerce.html) in 2019,
@@ -41,7 +41,9 @@
   location: https://github.com/shlevy/parametric-functor
 
 library
-  exposed-modules:  Data.Functor.Parametric
-  build-depends:    base >= 4.12 && < 5
+  exposed-modules:
+    Control.Monad.Trans.Class.Parametric
+    Data.Functor.Parametric
+  build-depends:    base >= 4.12 && < 5, transformers >= 0.2 && < 1.0
   hs-source-dirs:   src
   default-language: Haskell98
diff --git a/src/Control/Monad/Trans/Class/Parametric.hs b/src/Control/Monad/Trans/Class/Parametric.hs
new file mode 100644
--- /dev/null
+++ b/src/Control/Monad/Trans/Class/Parametric.hs
@@ -0,0 +1,53 @@
+-- Copyright 2024 Shea Levy
+--
+-- Licensed under the Apache License, Version 2.0 (the "License");
+-- you may not use this file except in compliance with the License.
+-- You may obtain a copy of the License at
+--
+--     http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MonoLocalBinds #-}
+{-# LANGUAGE QuantifiedConstraints #-}
+{-# LANGUAGE UndecidableInstances #-}
+{-# LANGUAGE UnicodeSyntax #-}
+
+{- |
+Description : 'MonadTrans'formers that preserve t'ParametricFunctor'
+Copyright   : Copyright 2024 Shea Levy.
+License     : Apache-2.0
+Maintainer  : shea@shealevy.com
+-}
+module Control.Monad.Trans.Class.Parametric where
+
+import Control.Monad.Trans.Class
+import Data.Coerce
+import Data.Functor.Parametric
+
+-- | 'MonadTrans'formers that preserve t'ParametricFunctor'
+class
+  ( MonadTrans t
+  , ∀ m x y
+     . ( Monad m
+       , ParametricFunctor m
+       , Coercible x y
+       )
+    ⇒ Coercible (t m x) (t m y)
+  ) ⇒
+  ParametricMonadTrans t
+
+instance
+  ( MonadTrans t
+  , ∀ m x y
+     . ( Monad m
+       , ParametricFunctor m
+       , Coercible x y
+       )
+    ⇒ Coercible (t m x) (t m y)
+  )
+  ⇒ ParametricMonadTrans t