diff --git a/Language/Haskell/GhcMod/Cabal21.hs b/Language/Haskell/GhcMod/Cabal21.hs
new file mode 100644
index 0000000..164e5d6
--- /dev/null
+++ b/Language/Haskell/GhcMod/Cabal21.hs
@@ -0,0 +1,73 @@
+-- Copyright   :  Isaac Jones 2003-2004
+{- All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Isaac Jones nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -}
+
+-- | ComponentLocalBuildInfo for Cabal >= 1.21
+module Language.Haskell.GhcMod.Cabal21 (
+    ComponentLocalBuildInfo
+  , PackageIdentifier(..)
+  , PackageName(..)
+  , componentPackageDeps
+  , componentLibraries
+  ) where
+
+import Distribution.Package (InstalledPackageId)
+import Data.Version (Version)
+
+data LibraryName = LibraryName String
+    deriving (Read, Show)
+
+newtype PackageName = PackageName { unPackageName :: String }
+  deriving (Read, Show)
+
+data PackageIdentifier
+  = PackageIdentifier {
+    pkgName :: PackageName,
+    pkgVersion :: Version
+  }
+  deriving (Read, Show)
+
+type PackageId = PackageIdentifier
+
+data ComponentLocalBuildInfo
+  = LibComponentLocalBuildInfo {
+    componentPackageDeps :: [(InstalledPackageId, PackageId)],
+    componentLibraries :: [LibraryName]
+  }
+  | ExeComponentLocalBuildInfo {
+    componentPackageDeps :: [(InstalledPackageId, PackageId)]
+  }
+  | TestComponentLocalBuildInfo {
+    componentPackageDeps :: [(InstalledPackageId, PackageId)]
+  }
+  | BenchComponentLocalBuildInfo {
+    componentPackageDeps :: [(InstalledPackageId, PackageId)]
+  }
+  deriving (Read, Show)
diff --git a/Language/Haskell/GhcMod/CabalConfig.hs b/Language/Haskell/GhcMod/CabalConfig.hs
index 2adcd4a..6bf44b7 100644
--- a/Language/Haskell/GhcMod/CabalConfig.hs
+++ b/Language/Haskell/GhcMod/CabalConfig.hs
@@ -15,6 +15,7 @@ import Language.Haskell.GhcMod.Types
 
 import qualified Language.Haskell.GhcMod.Cabal16 as C16
 import qualified Language.Haskell.GhcMod.Cabal18 as C18
+import qualified Language.Haskell.GhcMod.Cabal21 as C21
 
 #ifndef MIN_VERSION_mtl
 #define MIN_VERSION_mtl(x,y,z) 1
@@ -31,7 +32,8 @@ import Data.Maybe ()
 import Data.Set ()
 import Data.List (find,tails,isPrefixOf,isInfixOf,nub,stripPrefix)
 import Distribution.Package (InstalledPackageId(..)
-                           , PackageIdentifier)
+                           , PackageIdentifier(..)
+                           , PackageName(..))
 import Distribution.Simple.BuildPaths (defaultDistPref)
 import Distribution.Simple.Configure (localBuildInfoFile)
 import Distribution.Simple.LocalBuildInfo (ComponentName)
@@ -77,7 +79,7 @@ configDependencies :: PackageIdentifier -> CabalConfig -> [Package]
 configDependencies thisPkg config = map fromInstalledPackageId deps
  where
     deps :: [InstalledPackageId]
-    deps = case deps18 `mplus` deps16 of
+    deps = case deps21 `mplus` deps18 `mplus` deps16 of
         Right ps -> ps
         Left msg -> error msg
 
@@ -85,7 +87,27 @@ configDependencies thisPkg config = map fromInstalledPackageId deps
     -- defined in the same package).
     internal pkgid = pkgid == thisPkg
 
-    -- Cabal >= 1.18
+    -- Cabal >= 1.21
+    deps21 :: Either String [InstalledPackageId]
+    deps21 =
+        map fst
+      <$> filterInternal21
+      <$> (readEither =<< extractField config "componentsConfigs")
+
+    filterInternal21
+        :: [(ComponentName, C21.ComponentLocalBuildInfo, [ComponentName])]
+        -> [(InstalledPackageId, C21.PackageIdentifier)]
+
+    filterInternal21 ccfg = [ (ipkgid, pkgid)
+                          | (_,clbi,_)      <- ccfg
+                          , (ipkgid, pkgid) <- C21.componentPackageDeps clbi
+                          , not (internal . packageIdentifierFrom21 $ pkgid) ]
+
+    packageIdentifierFrom21 :: C21.PackageIdentifier -> PackageIdentifier
+    packageIdentifierFrom21 (C21.PackageIdentifier (C21.PackageName myName) myVersion) =
+        PackageIdentifier (PackageName myName) myVersion
+
+    -- Cabal >= 1.18 && < 1.21
     deps18 :: Either String [InstalledPackageId]
     deps18 =
           map fst
diff --git a/ghc-mod.cabal b/ghc-mod.cabal
index b559cc0..d14ffa3 100644
--- a/ghc-mod.cabal
+++ b/ghc-mod.cabal
@@ -61,6 +61,7 @@ Library
                         Language.Haskell.GhcMod.Browse
                         Language.Haskell.GhcMod.Cabal16
                         Language.Haskell.GhcMod.Cabal18
+                        Language.Haskell.GhcMod.Cabal21
                         Language.Haskell.GhcMod.CabalApi
                         Language.Haskell.GhcMod.CabalConfig
                         Language.Haskell.GhcMod.CaseSplit