diff --git a/dev-gap/atlasrep/Manifest b/dev-gap/atlasrep/Manifest
index 7a38fac7ed0bd..3cfda220bab2d 100644
--- a/dev-gap/atlasrep/Manifest
+++ b/dev-gap/atlasrep/Manifest
@@ -1,3 +1,4 @@
 DIST atlasrep-2.1.7-testdata.tar.xz 386468 BLAKE2B d1ef21fa465514fd48acf09b9a73bee91f35093541ae50d734343a9d2daf9590039f6afacb242723a49d25000e678ec13d56635e12a85d72a9fa8eaf936abdfd SHA512 065719e35733c28cd46bab7c719ea70ce61e6fde7fffe722d8d98eeef39d385dc298ed562c739cb45ee3f61a1c2942cdd465a7f043b190a2117db97dbba984f2
 DIST atlasrep-2.1.8.tar.gz 2239968 BLAKE2B be13eeff4a56fcf8f84397e5218f72ba1a830bf154702072ef0172b031b0718d0675c2c14d27933ada8bd8d1a78dfb401d7600ea5194d2c4a1a86e99f29752fd SHA512 6f8a8edc5d7b4f1da3e9ac5df33b29aacfa1e16f202e9b6376ce74c1f75c55a436117c1adb18300f96ad2d9962d07c88bf9709ca26ec60d2f851b051ba32160e
+DIST atlasrep-2.1.9.tar.gz 2290567 BLAKE2B 5880f4baf5252d6700ac65706efed140d9c3861a3f67f19db06c675086eab7da29cb7ac687a61d36d9bcb3692b115eda472b3e7440ab231cc3a6bef5ab16a573 SHA512 81399ff8de094148bc501dc1591722b64038d8b31c7dd3fbb66209a5f46044ef4b798f71ab56632d765c3d970a4c333e708bcd6a5cd2ceff54005981d9ab0bc3
 DIST atlasrepdata.tar.gz 22203132 BLAKE2B 1bc5f9c4045b46ab98d48482569134ac8141868fdb3082b453a9a90dfbf8c780faa6da177d0db115dcdd59a04fe1dbbea662a598b2a53cc81a79a88cfb3f6ee0 SHA512 fc1d594eb23486163081360f63c63ee6b81e7cc72f97c3c5a377d7cfd7f93ce1ae0228ba9bd3032f9d1e2ea68150524bbb4a98b73507458d6e23692b35de3151
diff --git a/dev-gap/atlasrep/atlasrep-2.1.9.ebuild b/dev-gap/atlasrep/atlasrep-2.1.9.ebuild
new file mode 100644
index 0000000000000..30767e9aedc72
--- /dev/null
+++ b/dev-gap/atlasrep/atlasrep-2.1.9.ebuild
@@ -0,0 +1,63 @@
+# Copyright 1999-2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit gap-pkg
+
+DESCRIPTION="GAP Interface to the Atlas of Group Representations"
+
+# How to make the test data:
+#
+#   gap> SetUserPreference("AtlasRep", "AtlasRepDataDirectory", "some-dir");
+#   gap> SetUserPreference("AtlasRep", "AtlasRepAccessRemoteFiles", true);
+#   gap> TestPackage("atlasrep"); TestPackage("orb"); ...
+#
+# Then tar up some-dir. This runs the test suite with downloading enabled,
+# so you wind up downloading all of the data you need into some-dir (which
+# has to be writable).
+SRC_URI="https://www.math.rwth-aachen.de/~Thomas.Breuer/atlasrep/${P}.tar.gz
+	https://www.math.rwth-aachen.de/homes/Thomas.Breuer/atlasrep/atlasrepdata.tar.gz
+	https://dev.gentoo.org/~mjo/distfiles/${PN}-2.1.7-testdata.tar.xz"
+
+LICENSE="GPL-3+"
+SLOT="0"
+KEYWORDS="~amd64 ~riscv"
+IUSE="test"
+RESTRICT="!test? ( test )"
+
+RDEPEND="dev-gap/io
+	dev-gap/utils"
+
+BDEPEND="test? (
+	dev-gap/ctbllib
+	dev-gap/tomlib
+)"
+gap-pkg_enable_tests
+
+PATCHES=(
+	"${FILESDIR}/${PN}-2.1.7-no-remote-access.patch"
+	"${FILESDIR}/${PN}-2.1.9-non-writable-data-dir.patch"
+)
+
+GAP_PKG_EXTRA_INSTALL=(
+	atlasprm.json
+	atlasprm_SHA.json
+	bibl
+	dataext
+	datagens
+	datapkg
+	dataword
+)
+
+src_prepare() {
+	# Move the pre-downloaded data into the empty directories where the
+	# package expects them to be. The archive atlasrepdata.tar.gz
+	# expands to a directory called "atlasrep".
+	for s in ext gens word; do
+		mv "${WORKDIR}/atlasrep/data${s}/"* "data${s}"/ || die
+	done
+	rm data{gens,word}/dummy || die
+
+	default
+}
diff --git a/dev-gap/atlasrep/files/atlasrep-2.1.9-non-writable-data-dir.patch b/dev-gap/atlasrep/files/atlasrep-2.1.9-non-writable-data-dir.patch
new file mode 100644
index 0000000000000..82ea59c8a95ed
--- /dev/null
+++ b/dev-gap/atlasrep/files/atlasrep-2.1.9-non-writable-data-dir.patch
@@ -0,0 +1,27 @@
+From 965555e07a73d20dd0c0b04cef2a922fb5471d78 Mon Sep 17 00:00:00 2001
+From: Michael Orlitzky <michael@orlitzky.com>
+Date: Tue, 1 Apr 2025 09:28:33 -0400
+Subject: [PATCH] gap/userpref.g: allow non-writable AtlasRepDataDirectory
+
+On Gentoo, all of the data is already there. So there's no reason to
+download it. So there's no requirement for the directory to be
+writable. (Remote access is disabled by default anyway.)
+---
+ gap/userpref.g | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/gap/userpref.g b/gap/userpref.g
+index 9c4cf6e..d685561 100644
+--- a/gap/userpref.g
++++ b/gap/userpref.g
+@@ -107,6 +107,7 @@ otherwise the default is an empty string."
+       fi;
+ 
+       dir:= DirectoriesPackageLibrary( "atlasrep", "" );
++      return Filename( dir, "" );
+       if ForAll( [ "dataext", "datagens", "dataword" ],
+                  subdir -> IsWritableFile( Filename( dir, subdir ) ) ) then
+         # The package directory is the first default.
+-- 
+2.49.0
+