diff --git a/pkgs/development/compilers/opendylan/default.nix b/pkgs/development/compilers/opendylan/default.nix
index 283ee2dffe47..fa0f98ea7fd2 100644
--- a/pkgs/development/compilers/opendylan/default.nix
+++ b/pkgs/development/compilers/opendylan/default.nix
@@ -39,5 +39,6 @@ stdenv.mkDerivation {
     description = "A multi-paradigm functional and object-oriented programming language";
     license = lib.licenses.mit;
     platforms = lib.platforms.linux;
+    broken = true; # last successful build 2020-12-11
   };
 }