diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
index 14da0c2..f2864b2 100644
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+Unreleased
+-----
+* Remove `Monoid` constraint from `MonadState` instance of `CPS.WriterT`
+
 2.3.2 -- 2025-12-07
 -----
 * Add `Accum` monad.
diff --git a/Control/Monad/State/Class.hs b/Control/Monad/State/Class.hs
index 73100a4..2752779 100644
--- a/Control/Monad/State/Class.hs
+++ b/Control/Monad/State/Class.hs
@@ -164,7 +164,7 @@ instance MonadState s m => MonadState s (ReaderT r m) where
     state = lift . state
 
 -- | @since 2.3
-instance (Monoid w, MonadState s m) => MonadState s (CPS.WriterT w m) where
+instance (MonadState s m) => MonadState s (CPS.WriterT w m) where
     get = lift get
     put = lift . put
     state = lift . state