diff --git a/hix.cabal b/hix.cabal
--- a/hix.cabal
+++ b/hix.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           hix
-version:        0.5.6
+version:        0.5.7
 synopsis:       Haskell/Nix development build tools
 description:    See https://hackage.haskell.org/package/hix/docs/Hix.html
 category:       Build
diff --git a/lib/Hix/Ghci.hs b/lib/Hix/Ghci.hs
--- a/lib/Hix/Ghci.hs
+++ b/lib/Hix/Ghci.hs
@@ -31,7 +31,14 @@
 import Hix.Json (jsonConfig)
 import Hix.Monad (M, noteGhci)
 import qualified Hix.Options as Options
-import Hix.Options (GhciOptions (GhciOptions), TargetSpec (TargetForFile), TestOptions (TestOptions))
+import Hix.Options (
+  ExtraGhciOptions,
+  ExtraGhcidOptions (ExtraGhcidOptions),
+  GhciOptions (GhciOptions),
+  GhcidOptions,
+  TargetSpec (TargetForFile),
+  TestOptions (TestOptions),
+  )
 import Hix.Path (rootDir)
 
 relativeToComponent ::
@@ -134,21 +141,24 @@
 
 searchPathArg :: NonEmpty (Path Abs Dir) -> Text
 searchPathArg paths =
-  [exon|-i#{colonSeparated}|]
+  [exon| -i#{colonSeparated}|]
   where
     colonSeparated = Text.intercalate ":" (pathText <$> toList paths)
 
 ghciCmdline ::
   GhciTest ->
+  Maybe ExtraGhciOptions ->
   Path Abs File ->
   Maybe (Path Abs File) ->
   GhciRun
-ghciCmdline test scriptFile runScriptFile =
+ghciCmdline test extra scriptFile runScriptFile =
   GhciRun {..}
   where
-    shell = [exon|##{Text.unwords (coerce test.args)} #{sp} -ghci-script=##{toFilePath scriptFile}|]
+    shell = [exon|##{Text.unwords (coerce test.args)}#{sp} -ghci-script=##{toFilePath scriptFile}#{extraOpts}|]
     run = runScriptFile <&> \ f -> [exon|-ghci-script=##{toFilePath f}|]
     sp = foldMap searchPathArg (nonEmpty test.searchPath)
+    extraOpts | Just o <- extra = [exon| ##{o}|]
+              | otherwise = ""
 
 ghciCmdlineFromOptions ::
   Path Abs Dir ->
@@ -158,15 +168,19 @@
   conf <- assemble opt
   shellScriptFile <- lift (ghciScriptFile tmp conf.script)
   runScriptFile <- lift (traverse (ghciScriptFile tmp) conf.test)
-  pure (ghciCmdline conf shellScriptFile runScriptFile)
+  pure (ghciCmdline conf opt.extra shellScriptFile runScriptFile)
 
 ghcidCmdlineFromOptions ::
   Path Abs Dir ->
-  GhciOptions ->
+  GhcidOptions ->
   M GhcidRun
 ghcidCmdlineFromOptions tmp opt = do
-  ghci <- ghciCmdlineFromOptions tmp opt
-  pure (GhcidRun [exon|ghcid --command="ghci #{ghci.shell}" --test='##{fromMaybe "main" ghci.test.test}'|] ghci)
+  ghci <- ghciCmdlineFromOptions tmp opt.ghci
+  let
+    test = fromMaybe "main" ghci.test.test
+  pure (GhcidRun [exon|ghcid --command="ghci #{ghci.shell}" --test='##{test}'#{foldMap extra opt.extra}|] ghci)
+  where
+    extra (ExtraGhcidOptions o) = [exon| ##{o}|]
 
 printGhciCmdline ::
   GhciOptions ->
@@ -177,7 +191,7 @@
   liftIO (Text.putStrLn [exon|ghci #{cmd.shell} #{fold cmd.run}|])
 
 printGhcidCmdline ::
-  GhciOptions ->
+  GhcidOptions ->
   M ()
 printGhcidCmdline opt = do
   tmp <- lift hixTempDir
diff --git a/lib/Hix/Options.hs b/lib/Hix/Options.hs
--- a/lib/Hix/Options.hs
+++ b/lib/Hix/Options.hs
@@ -98,15 +98,33 @@
   }
   deriving stock (Show, Generic)
 
+newtype ExtraGhciOptions =
+  ExtraGhciOptions Text
+  deriving stock (Eq, Show, Generic)
+  deriving newtype (IsString)
+
+newtype ExtraGhcidOptions =
+  ExtraGhcidOptions Text
+  deriving stock (Eq, Show, Generic)
+  deriving newtype (IsString)
+
 data GhciOptions =
   GhciOptions {
     config :: Either GhciConfig JsonConfig,
     root :: Maybe (Path Abs Dir),
     component :: TargetSpec,
-    test :: TestOptions
+    test :: TestOptions,
+    extra :: Maybe ExtraGhciOptions
   }
   deriving stock (Show, Generic)
 
+data GhcidOptions =
+  GhcidOptions {
+    ghci :: GhciOptions,
+    extra :: Maybe ExtraGhcidOptions
+  }
+  deriving stock (Show, Generic)
+
 data NewOptions =
   NewOptions {
     config :: NewProjectConfig
@@ -131,7 +149,7 @@
   |
   EnvRunner EnvRunnerCommandOptions
   |
-  GhcidCmd GhciOptions
+  GhcidCmd GhcidOptions
   |
   GhciCmd GhciOptions
   |
@@ -250,6 +268,14 @@
   cd <- cdParser
   pure TestOptions {..}
 
+extraGhciParser :: Parser (Maybe ExtraGhciOptions)
+extraGhciParser =
+  optional (strOption (long "ghci-options" <> help "Additional command line options to pass to ghci"))
+
+extraGhcidParser :: Parser (Maybe ExtraGhcidOptions)
+extraGhcidParser =
+  optional (strOption (long "ghcid-options" <> help "Additional command line options to pass to ghcid"))
+
 envParser :: Parser EnvRunnerCommandOptions
 envParser = do
   options <- do
@@ -266,8 +292,15 @@
   root <- rootParser
   component <- targetSpecParser
   test <- testOptionsParser
+  extra <- extraGhciParser
   pure GhciOptions {..}
 
+ghcidParser :: Parser GhcidOptions
+ghcidParser = do
+  ghci <- ghciParser
+  extra <- extraGhcidParser
+  pure GhcidOptions {..}
+
 newParser :: Parser NewOptions
 newParser = do
   name <- strOption (long "name" <> short 'n' <> help "The name of the new project and its main package")
@@ -289,7 +322,7 @@
   <>
   command "ghci-cmd" (GhciCmd <$> info ghciParser (progDesc "Print a ghci cmdline to load a module in a Hix env"))
   <>
-  command "ghcid-cmd" (GhcidCmd <$> info ghciParser (progDesc "Print a ghcid cmdline to run a function in a Hix env"))
+  command "ghcid-cmd" (GhcidCmd <$> info ghcidParser (progDesc "Print a ghcid cmdline to run a function in a Hix env"))
   <>
   command "new" (NewCmd <$> info newParser (progDesc "Create a new Hix project in the current directory"))
   <>
diff --git a/test/Hix/Test/GhciTest.hs b/test/Hix/Test/GhciTest.hs
--- a/test/Hix/Test/GhciTest.hs
+++ b/test/Hix/Test/GhciTest.hs
@@ -27,6 +27,7 @@
   ComponentSpec (ComponentSpec),
   EnvRunnerOptions (EnvRunnerOptions),
   GhciOptions (GhciOptions, component),
+  GhcidOptions (GhcidOptions),
   PackageSpec (PackageSpec),
   TargetSpec (TargetForComponent, TargetForFile),
   TestOptions (TestOptions),
@@ -89,8 +90,8 @@
     component = Just (ComponentSpec "test" (Just (SourceDir [reldir|test|])))
   }
 
-options :: GhciOptions
-options =
+ghciOptions :: GhciOptions
+ghciOptions =
   GhciOptions {
     config = Left GhciConfig {
       packages,
@@ -105,9 +106,14 @@
       test = Just "test_server",
       runner = Just "generic",
       cd = ChangeDir True
-    }
+    },
+    extra = Nothing
   }
 
+options :: GhcidOptions
+options =
+  GhcidOptions {ghci = ghciOptions, extra = Nothing}
+
 ghcidTarget ::
   Path Abs Dir ->
   Path Abs File ->
@@ -165,5 +171,5 @@
 
 test_moduleName :: TestT IO ()
 test_moduleName = do
-  conf <- evalEither =<< liftIO (runM root (assemble options { component = spec4 }))
+  conf <- evalEither =<< liftIO (runM root (assemble options.ghci { component = spec4 }))
   target_moduleName === conf.script