diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Revision history for pinned-warnings
 
+## 0.1.0.13
+
+* Support GHC 9.4.x
+
 ## 0.1.0.0 -- YYYY-mm-dd
 
 * First version. Released on an unsuspecting world.
diff --git a/pinned-warnings.cabal b/pinned-warnings.cabal
--- a/pinned-warnings.cabal
+++ b/pinned-warnings.cabal
@@ -4,7 +4,7 @@
 -- http://haskell.org/cabal/users-guide/
 
 name:                pinned-warnings
-version:             0.1.0.12
+version:             0.1.0.13
 synopsis: Preserve warnings in a GHCi session
 description: Please see the README on GitHub at <https://github.com/aaronallen8455/pinned-warnings#readme>
 homepage:       https://github.com/aaronallen8455/pinned-warnings#readme
@@ -19,7 +19,7 @@
 extra-source-files:
   README.md
   CHANGELOG.md
-tested-with: GHC ==8.10.4 || ==8.10.5 || ==8.10.6 || ==8.10.7 || ==9.0.1 || ==9.2.2
+tested-with: GHC ==8.10.4 || ==8.10.5 || ==8.10.6 || ==8.10.7 || ==9.0.1 || ==9.2.2 || ==9.4.2
 
 library
   exposed-modules:     PinnedWarnings
@@ -28,7 +28,7 @@
                        Internal.GhcFacade
                        Internal.Types
 
-  build-depends:       ghc              >= 8.10 && < 9.3,
+  build-depends:       ghc              >= 8.10 && < 9.5,
                        base             >= 4.14.1 && < 5,
                        bytestring       >= 0.10.12,
                        containers       >= 0.6.2,
diff --git a/src/Internal/GhcFacade.hs b/src/Internal/GhcFacade.hs
--- a/src/Internal/GhcFacade.hs
+++ b/src/Internal/GhcFacade.hs
@@ -7,9 +7,10 @@
 #else
   , log_action'
 #endif
+  , TcPluginResult'
   ) where
 
-#if MIN_VERSION_ghc(9,2,0)
+#if MIN_VERSION_ghc(9,4,0)
 import GHC as X hiding (FunDep)
 import GHC.Core.Class as X
 import GHC.Core.Make as X
@@ -18,7 +19,28 @@
 import GHC.Data.IOEnv as X
 import GHC.Driver.Plugins as X hiding (TcPlugin)
 import GHC.Driver.Env.Types as X
+import GHC.Tc.Errors.Types as X
 import GHC.Tc.Plugin as X
+import GHC.Tc.Types as X hiding (DefaultingPlugin)
+import GHC.Tc.Types.Constraint as X
+import GHC.Tc.Types.Evidence as X
+import GHC.Types.Error as X
+import GHC.Types.Name.Occurrence as X
+import GHC.Types.SrcLoc as X
+import GHC.Utils.Error as X
+import GHC.Utils.Logger as X
+import GHC.Utils.Outputable as X
+
+#elif MIN_VERSION_ghc(9,2,0)
+import GHC as X hiding (FunDep)
+import GHC.Core.Class as X
+import GHC.Core.Make as X
+import GHC.Data.Bag as X
+import GHC.Data.FastString as X
+import GHC.Data.IOEnv as X
+import GHC.Driver.Plugins as X hiding (TcPlugin)
+import GHC.Driver.Env.Types as X
+import GHC.Tc.Plugin as X
 import GHC.Tc.Types as X
 import GHC.Tc.Types.Constraint as X
 import GHC.Tc.Types.Evidence as X
@@ -89,4 +111,10 @@
 log_action' action withStuff dflags warnReason severity srcSpan pprStyle msgDoc = do
   withStuff dflags severity srcSpan msgDoc
   action dflags warnReason severity srcSpan pprStyle msgDoc
+#endif
+
+#if MIN_VERSION_ghc(9,4,0)
+type TcPluginResult' = X.TcPluginSolveResult
+#else
+type TcPluginResult' = X.TcPluginResult
 #endif
diff --git a/src/Internal/Types.hs b/src/Internal/Types.hs
--- a/src/Internal/Types.hs
+++ b/src/Internal/Types.hs
@@ -10,6 +10,7 @@
   ) where
 
 import qualified Data.Map.Strict as M
+import           Data.Ord (comparing)
 import qualified Data.Set as S
 import           Data.Time
 
@@ -19,7 +20,9 @@
 
 newtype Warning = Warning
   { unWarning
-#if MIN_VERSION_ghc(9,2,0)
+#if MIN_VERSION_ghc(9,4,0)
+      :: Ghc.MsgEnvelope Ghc.DiagnosticMessage
+#elif MIN_VERSION_ghc(9,2,0)
       :: Ghc.MsgEnvelope Ghc.DecoratedSDoc
 #else
       :: Ghc.WarnMsg
@@ -28,12 +31,20 @@
 
 showWarning :: Warning -> String
 showWarning =
-#if MIN_VERSION_ghc(9,2,0)
+#if MIN_VERSION_ghc(9,4,0)
   let sdocCtx = Ghc.defaultSDocContext
               { Ghc.sdocPrintUnicodeSyntax = True
               , Ghc.sdocCanUseUnicode = True
               }
    in foldMap (Ghc.showSDocOneLine sdocCtx)
+      . Ghc.unDecorated . Ghc.diagnosticMessage
+      . Ghc.errMsgDiagnostic . unWarning
+#elif MIN_VERSION_ghc(9,2,0)
+  let sdocCtx = Ghc.defaultSDocContext
+              { Ghc.sdocPrintUnicodeSyntax = True
+              , Ghc.sdocCanUseUnicode = True
+              }
+   in foldMap (Ghc.showSDocOneLine sdocCtx)
       . Ghc.unDecorated . Ghc.errMsgDiagnostic . unWarning
 #else
   show . unWarning
@@ -43,7 +54,7 @@
   Warning a == Warning b = show a == show b
 
 instance Ord Warning where
-  compare (Warning a) (Warning b) = compare (show a) (show b)
+  compare = comparing (show . unWarning)
 
 newtype MonoidMap k a = MonoidMap (M.Map k a)
   deriving Foldable
diff --git a/src/PinnedWarnings.hs b/src/PinnedWarnings.hs
--- a/src/PinnedWarnings.hs
+++ b/src/PinnedWarnings.hs
@@ -52,6 +52,9 @@
     { Ghc.tcPluginInit  = initTcPlugin
     , Ghc.tcPluginSolve = \pluginState _ _ -> checkWanteds pluginState
     , Ghc.tcPluginStop  = const $ pure ()
+#if MIN_VERSION_ghc(9,4,0)
+    , Ghc.tcPluginRewrite = mempty
+#endif
     }
 
 data PluginState =
@@ -75,7 +78,11 @@
 lookupClass className = do
   result <- Ghc.findImportedModule
               (Ghc.mkModuleName "ShowWarnings")
+#if MIN_VERSION_ghc(9,4,0)
+              Ghc.NoPkgQual
+#else
               (Just "pinned-warnings")
+#endif
 
   case result of
     Ghc.Found _ mod' -> do
@@ -88,7 +95,7 @@
 -- warnings into GHC.
 checkWanteds :: PluginState
              -> [Ghc.Ct]
-             -> Ghc.TcPluginM Ghc.TcPluginResult
+             -> Ghc.TcPluginM Ghc.TcPluginResult'
 checkWanteds pluginState
     = fmap (flip Ghc.TcPluginOk [] . catMaybes)
     . traverse go
@@ -136,8 +143,12 @@
              <$> Ghc.tcPluginIO (readMVar globalState)
 
   Ghc.tcPluginIO . atomicModifyIORef' errsRef
-#if MIN_VERSION_ghc(9,2,0)
+#if MIN_VERSION_ghc(9,4,0)
     $ \messages ->
+        (Ghc.mkMessages ((fmap . fmap) Ghc.TcRnUnknownMessage pinnedWarns)
+          `Ghc.unionMessages` messages, ())
+#elif MIN_VERSION_ghc(9,2,0)
+    $ \messages ->
         (Ghc.mkMessages pinnedWarns `Ghc.unionMessages` messages, ())
 #else
     $ \(warnings, errors) ->
@@ -161,8 +172,13 @@
 -- This occurs before any new warnings are captured for the module.
 resetPinnedWarnsForMod
   :: Ghc.ModSummary
+#if MIN_VERSION_ghc(9,4,0)
+  -> Ghc.ParsedResult
+  -> Ghc.Hsc Ghc.ParsedResult
+#else
   -> Ghc.HsParsedModule
   -> Ghc.Hsc Ghc.HsParsedModule
+#endif
 resetPinnedWarnsForMod modSummary parsedModule = do
   let modFile = fromString $ Ghc.ms_hspp_file modSummary
 
@@ -172,7 +188,37 @@
   pure parsedModule
 
 -- | Taps into the log action to capture the warnings that GHC emits.
-#if MIN_VERSION_ghc(9,2,0)
+#if MIN_VERSION_ghc(9,4,0)
+addWarningCapture :: Ghc.HscEnv -> Ghc.HscEnv
+addWarningCapture hscEnv =
+  hscEnv
+    { Ghc.hsc_logger = Ghc.pushLogHook warningsHook (Ghc.hsc_logger hscEnv)
+    }
+  where
+    warningsHook :: Ghc.LogAction -> Ghc.LogAction
+    warningsHook logAction dynFlags messageClass srcSpan sdoc = do
+      case messageClass of
+        Ghc.MCDiagnostic Ghc.SevWarning _
+          | Ghc.RealSrcLoc' start <- Ghc.srcSpanStart srcSpan
+          , Ghc.RealSrcLoc' end <- Ghc.srcSpanEnd srcSpan
+          , Just modFile <- Ghc.srcSpanFileName_maybe srcSpan
+          -> do
+            let diag =
+                  Ghc.DiagnosticMessage
+                    { Ghc.diagMessage = Ghc.mkSimpleDecorated sdoc
+                    , Ghc.diagReason = Ghc.WarningWithoutFlag
+                    , Ghc.diagHints = []
+                    }
+                warn = Warning Ghc.MsgEnvelope
+                  { Ghc.errMsgSpan = srcSpan
+                  , Ghc.errMsgContext = Ghc.neverQualify
+                  , Ghc.errMsgDiagnostic = diag
+                  , Ghc.errMsgSeverity = Ghc.SevWarning
+                  }
+            addWarningToGlobalState start end modFile warn
+        _ -> pure ()
+      logAction dynFlags messageClass srcSpan sdoc
+#elif MIN_VERSION_ghc(9,2,0)
 addWarningCapture :: Ghc.HscEnv -> Ghc.HscEnv
 addWarningCapture hscEnv =
   hscEnv