diff --git a/app/Main.hs b/app/Main.hs
index d2c824b..a4c9b2b 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -15,21 +15,15 @@ import Paths_ormolu (version)
 import System.Exit (ExitCode (..), exitWith)
 import System.IO (hPutStrLn, stderr)
 import qualified Data.Text.IO as TIO
-import qualified Data.Yaml as Yaml
 
 -- | Entry point of the program.
 
 main :: IO ()
 main = withPrettyOrmoluExceptions $ do
   Opts {..} <- execParser optsParserInfo
-  config <- case optConfigFile of
-    Nothing -> return optConfig
-    Just path -> do
-      config <- Yaml.decodeFileThrow path
-      return (config <> optConfig)
   r <- case optInputFile of
-    "-" -> ormoluStdin config
-    inputFile -> ormoluFile config inputFile
+    "-" -> ormoluStdin optConfig
+    inputFile -> ormoluFile optConfig inputFile
   let notForStdin = do
         when (optInputFile == "-") $ do
           hPutStrLn
@@ -58,8 +52,6 @@ main = withPrettyOrmoluExceptions $ do
 data Opts = Opts
   { optMode :: !Mode
     -- ^ Mode of operation
-  , optConfigFile :: !(Maybe FilePath)
-    -- ^ Location of configuration file (optional)
   , optConfig :: !Config
     -- ^ Ormolu 'Config'
   , optInputFile :: !FilePath
@@ -107,12 +99,6 @@ optsParser = Opts
     , value Stdout
     , help "Mode of operation: 'stdout', 'inplace', or 'check'"
     ]
-  <*> (optional . strOption . mconcat)
-    [ long "config"
-    , short 'c'
-    , metavar "CONFIG"
-    , help "Location of configuration file"
-    ]
   <*> configParser
   <*> (strArgument . mconcat)
     [ metavar "FILE"
diff --git a/ormolu.cabal b/ormolu.cabal
index 69e2261..58bae5e 100644
--- a/ormolu.cabal
+++ b/ormolu.cabal
@@ -47,7 +47,6 @@ library
                     , mtl            >= 2.0 && < 3.0
                     , syb            >= 0.7 && < 0.8
                     , text           >= 0.2 && < 1.3
-                    , yaml           >= 0.8 && < 0.12
   exposed-modules:    Ormolu
                     , Ormolu.Config
                     , Ormolu.Diff
@@ -126,7 +125,6 @@ executable ormolu
                     , optparse-applicative >= 0.14 && < 0.15
                     , ormolu
                     , text           >= 0.2 && < 1.3
-                    , yaml           >= 0.8 && < 0.12
   other-modules:      Paths_ormolu
   if flag(dev)
     ghc-options:      -Wall -Werror -Wcompat
diff --git a/src/Ormolu/Config.hs b/src/Ormolu/Config.hs
index 4c00640..0898ef3 100644
--- a/src/Ormolu/Config.hs
+++ b/src/Ormolu/Config.hs
@@ -12,7 +12,6 @@ module Ormolu.Config
   )
 where
 
-import Data.Yaml
 import qualified SrcLoc as GHC
 
 -- | Ormolu configuration.
@@ -26,24 +25,6 @@ data Config = Config
     -- ^ Output information useful for debugging
   } deriving (Eq, Show)
 
-instance Semigroup Config where
-  a <> b = Config
-    { cfgDynOptions = cfgDynOptions a <> cfgDynOptions b
-    , cfgUnsafe = cfgUnsafe a || cfgUnsafe b
-    , cfgDebug = cfgDebug a || cfgDebug b
-    }
-
-instance Monoid Config where
-  mempty = defaultConfig
-  mappend = (<>)
-
-instance FromJSON Config where
-  parseJSON = withObject "config" $ \o -> do
-    cfgDynOptions <- o .: "ghc-opts"
-    cfgUnsafe <- o .: "unsafe"
-    cfgDebug <- o .: "debug"
-    return Config {..}
-
 -- | Default 'Config'.
 
 defaultConfig :: Config
@@ -57,7 +38,7 @@ defaultConfig = Config
 
 newtype DynOption = DynOption
   { unDynOption :: String
-  } deriving (Eq, Ord, Show, FromJSON)
+  } deriving (Eq, Ord, Show)
 
 -- | Convert 'DynOption' to @'GHC.Located' 'String'@.