diff --git a/pkgs/by-name/at/ats/install-atsdoc-hats-files.patch b/pkgs/by-name/at/ats/install-atsdoc-hats-files.patch
deleted file mode 100644
index 93c6fa07d8a6..000000000000
--- a/pkgs/by-name/at/ats/install-atsdoc-hats-files.patch
+++ /dev/null
@@ -1,38 +0,0 @@
---- ats-lang-anairiats-0.2.11/Makefile	2013-12-10 00:43:52.000000000 +0100
-+++ ats-lang-anairiats-0.2.11/Makefile	2014-03-02 07:49:06.985837425 +0100
-@@ -97,7 +97,7 @@
- 	cd $(abs_top_srcdir)
- 	[ -d $(bindir2) ] || $(MKDIR_P) $(bindir2)
- 	$(MKDIR_P) $(ATSLIBHOME2)/bin
--	find ccomp contrib doc libats libc prelude -type d \
-+	find ccomp contrib doc libats libatsdoc libc prelude -type d \
- 	  -exec $(MKDIR_P) $(ATSLIBHOME2)/\{} \; \
- 	  -print
- 
-@@ -105,7 +105,7 @@
- #
- # recursively install all files in the list except .svn control files.
- #
--	for d in ccomp/runtime contrib doc libats libc prelude; do \
-+	for d in ccomp/runtime contrib doc libats libatsdoc libc prelude; do \
- 	  cd $(abs_top_srcdir) && \
- 	  $(INSTALL) -d $(ATSLIBHOME2)/"$$d" && \
- 	  find "$$d" -name .svn -prune -o -type f \
-@@ -143,6 +143,17 @@
- 	  $(INSTALL) -m 755 ats_env.sh $(bindir2)/"$$b" && \
- 	  echo [ats_env.sh] is installed into $(bindir2)/"$$b"; \
- 	done
-+#
-+# install atsdoc headers
-+#
-+	for f in \
-+	    utils/atsdoc/SATS/*.sats utils/atsdoc/DATS/*.dats utils/atsdoc/HATS/*.hats; \
-+	do \
-+	  [ -f "$$f" ] || continue; \
-+	  cd $(abs_top_srcdir) && \
-+	  $(INSTALL) -m 644 -D "$$f" $(ATSLIBHOME2)/"$$f" && \
-+	  echo "$$f"; \
-+	done
- 
- install:: install_files
- 
diff --git a/pkgs/by-name/at/ats/package.nix b/pkgs/by-name/at/ats/package.nix
deleted file mode 100644
index 227702fb316b..000000000000
--- a/pkgs/by-name/at/ats/package.nix
+++ /dev/null
@@ -1,30 +0,0 @@
-{
-  lib,
-  stdenv,
-  fetchurl,
-  gmp,
-}:
-
-stdenv.mkDerivation rec {
-  pname = "ats";
-  version = "0.2.12";
-
-  src = fetchurl {
-    url = "mirror://sourceforge/ats-lang/ats-lang-anairiats-${version}.tgz";
-    sha256 = "0l2kj1fzhxwsklwmn5yj2vp9rmw4jg0b18bzwqz72bfi8i39736k";
-  };
-
-  # this is necessary because atxt files usually include some .hats files
-  patches = [ ./install-atsdoc-hats-files.patch ];
-  buildInputs = [ gmp ];
-
-  meta = {
-    description = "Functional programming language with dependent types";
-    homepage = "http://www.ats-lang.org";
-    license = lib.licenses.gpl3Plus;
-    # TODO: it looks like ATS requires gcc specifically. Someone with more knowledge
-    # will need to experiment.
-    platforms = lib.platforms.linux;
-    maintainers = [ lib.maintainers.thoughtpolice ];
-  };
-}
diff --git a/pkgs/top-level/aliases.nix b/pkgs/top-level/aliases.nix
index 62d29b6bdb51..aee1413e3903 100644
--- a/pkgs/top-level/aliases.nix
+++ b/pkgs/top-level/aliases.nix
@@ -311,6 +311,7 @@ mapAliases {
   atlassian-confluence = throw "Atlassian software has been removed, as support for the Atlassian Server products ended in February 2024 and there was insufficient interest in maintaining the Atlassian Data Center replacements"; # Added 2024-11-02
   atlassian-crowd = throw "Atlassian software has been removed, as support for the Atlassian Server products ended in February 2024 and there was insufficient interest in maintaining the Atlassian Data Center replacements"; # Added 2024-11-02
   atlassian-jira = throw "Atlassian software has been removed, as support for the Atlassian Server products ended in February 2024 and there was insufficient interest in maintaining the Atlassian Data Center replacements"; # Added 2024-11-02
+  ats = throw "'ats' has been removed as it is unmaintained for 10 years and broken"; # Added 2025-05-17
   audaciousQt5 = throw "'audaciousQt5' has been removed, since audacious is built with Qt 6 now"; # Added 2024-07-06
   auditBlasHook = throw "'auditBlasHook' has been removed since it never worked"; # Added 2024-04-02
   aumix = throw "'aumix' has been removed due to lack of maintenance upstream. Consider using 'pamixer' for CLI or 'pavucontrol' for GUI"; # Added 2024-09-14