diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## [0.13.0.3] - 2023-03-27
+
+### Added
+
+* Compatibility with `mtl-2.3`
+
 ## [0.13.0.2] - 2023-03-24
 
 ### Changed
diff --git a/src/Test/Syd/Expectation.hs b/src/Test/Syd/Expectation.hs
--- a/src/Test/Syd/Expectation.hs
+++ b/src/Test/Syd/Expectation.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TypeApplications #-}
 {-# OPTIONS_GHC -fno-warn-redundant-constraints #-}
@@ -6,6 +7,9 @@
 module Test.Syd.Expectation where
 
 import Control.Exception
+#if MIN_VERSION_mtl(2,3,0)
+import Control.Monad (unless, when)
+#endif
 import Control.Monad.Reader
 import Data.ByteString (ByteString)
 import Data.List
diff --git a/src/Test/Syd/Runner/Asynchronous.hs b/src/Test/Syd/Runner/Asynchronous.hs
--- a/src/Test/Syd/Runner/Asynchronous.hs
+++ b/src/Test/Syd/Runner/Asynchronous.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE LambdaCase #-}
@@ -16,6 +17,9 @@
 import Control.Concurrent
 import Control.Concurrent.Async as Async
 import Control.Exception
+#if MIN_VERSION_mtl(2,3,0)
+import Control.Monad (when)
+#endif
 import Control.Monad.Reader
 import Data.Maybe
 import Data.Set (Set)
diff --git a/sydtest.cabal b/sydtest.cabal
--- a/sydtest.cabal
+++ b/sydtest.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           sydtest
-version:        0.13.0.2
+version:        0.13.0.3
 synopsis:       A modern testing framework for Haskell with good defaults and advanced testing features.
 description:    A modern testing framework for Haskell with good defaults and advanced testing features. Sydtest aims to make the common easy and the hard possible. See https://github.com/NorfairKing/sydtest#readme for more information.
 category:       Testing