diff --git a/pkgs/development/haskell-modules/configuration-common.nix b/pkgs/development/haskell-modules/configuration-common.nix
index cdb15fd9f814..13063aeb9751 100644
--- a/pkgs/development/haskell-modules/configuration-common.nix
+++ b/pkgs/development/haskell-modules/configuration-common.nix
@@ -899,4 +899,7 @@ self: super: {
     sha256 = "1vss7b99zrhw3r29krl1b60r4qk0m2mpwmrz8q8zdxrh33hb8pd7";
   });
 
+  # happy 1.19.6 and later break some packages.
+  Agda = super.Agda.override { happy = self.happy_1_19_5; };
+
 }