diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
index b5d214c579ce..c96c166d5eaf 100644
--- a/pkgs/top-level/haskell-packages.nix
+++ b/pkgs/top-level/haskell-packages.nix
@@ -111,8 +111,8 @@ in {
           packages.ghc8107Binary;
       inherit (buildPackages.python3Packages) sphinx;
       inherit (buildPackages.darwin) autoSignDarwinBinariesHook;
-      buildLlvmPackages = buildPackages.llvmPackages_10;
-      llvmPackages = pkgs.llvmPackages_10;
+      buildLlvmPackages = buildPackages.llvmPackages_9;
+      llvmPackages = pkgs.llvmPackages_9;
     };
     ghc921 = callPackage ../development/compilers/ghc/9.2.1.nix {
       bootPkgs =