diff --git a/pkgs/development/haskell-modules/generic-stack-builder.nix b/pkgs/development/haskell-modules/generic-stack-builder.nix
index 591de1236d42..2afe270e0fc8 100644
--- a/pkgs/development/haskell-modules/generic-stack-builder.nix
+++ b/pkgs/development/haskell-modules/generic-stack-builder.nix
@@ -33,7 +33,7 @@ in stdenv.mkDerivation (args // {
   STACK_PLATFORM_VARIANT="nix";
   STACK_IN_NIX_SHELL=1;
   STACK_IN_NIX_EXTRA_ARGS = extraArgs;
-  shellHook = addStackArgsHook;
+  shellHook = addStackArgsHook + args.shellHook or "";
 
 
   # XXX: workaround for https://ghc.haskell.org/trac/ghc/ticket/11042.