diff --git a/dev-python/xmlsec/Manifest b/dev-python/xmlsec/Manifest
new file mode 100644
index 000000000..bf8dd6bd3
--- /dev/null
+++ b/dev-python/xmlsec/Manifest
@@ -0,0 +1,4 @@
+AUX xmlsec-1.3.11-fix-xml-testfail.patch 879 BLAKE2B 3d655b40a67b44a4abd65188c6d719e12063e857942fdb112b47da38977864252e3d250e0bbaf5c86f4688bb7701aae89df444c4fef0e3f0eaffc98fe5b6b856 SHA512 8c8f9af415dc9207e5c0599ee958dff6558618f94a9cb3c583b1c9eb6d1de251d714edf1afdee581cb33c7543f88c54d36af9b6f903fe31994a86f1b602e4c75
+DIST python-xmlsec-1.3.12.gh.tar.gz 77722 BLAKE2B b5ecece8063b823cdbe4d58967d10026bdc6f3774954021a3739d579ba3c5a08130af1792921c7892e6bc3d00f88ac83ab30e862775e419e0dad40b990b10cbe SHA512 19c5e3bf58b4b0f8a1cca3e60c08348b02ae298620f8c02b8cfb325aecf0313cb2bd1af89507b754ebe4c35af3b031e232d15ddcd42deae0821c9c0d7571aa7c
+EBUILD xmlsec-1.3.12-r3.ebuild 1328 BLAKE2B 4133719a25c0e7ba2c5ea74925be88cfa36b971d0feabe6fbee780f2c68bd184c0704c49ec54e4369cfd912a8362f1af86483c7e75bb81a9854f8d0dc5155673 SHA512 3a332eb9d32878720f3281c71b6e57a23f8241a08633937408f0723ac2b7c19bf501fc0af8bd6f29643949d0cf51320fabb8d080d72c9f13ad9a258438814535
+MISC metadata.xml 480 BLAKE2B 17abd324963ad808438f7c04a5785ab72e280a5ba8b132737d89c06fd17fc20e96478b4684ae84864bd03690bda6e865200a8eacf3bd0c23ceca4f0230bef1a5 SHA512 82d2b54886ba9d2eeba17aa04e2946c9dda8d30a5bea9a9ba7a5041b559971466c33ceb67ed35c9f865c052df09fb9fd057b46efd4d3d4314f456c8b1c0aaac7
diff --git a/dev-python/xmlsec/files/xmlsec-1.3.11-fix-xml-testfail.patch b/dev-python/xmlsec/files/xmlsec-1.3.11-fix-xml-testfail.patch
new file mode 100644
index 000000000..3e7ab8829
--- /dev/null
+++ b/dev-python/xmlsec/files/xmlsec-1.3.11-fix-xml-testfail.patch
@@ -0,0 +1,23 @@
+Taken from: https://github.com/mehcode/python-xmlsec/issues/84#issuecomment-632930116
+diff --git a/tests/base.py b/tests/base.py
+index b05de1d..5ec356f 100644
+--- a/tests/base.py
++++ b/tests/base.py
+@@ -94,6 +94,7 @@ class TestMemoryLeaks(unittest.TestCase):
+ 
+     def load_xml(self, name, xpath=None):
+         """returns xml.etree"""
++        etree.set_default_parser(parser=etree.XMLParser())
+         root = etree.parse(self.path(name)).getroot()
+         if xpath is None:
+             return root
+diff --git a/tests/test_doc_examples.py b/tests/test_doc_examples.py
+index 2fc490f..53d2377 100644
+--- a/tests/test_doc_examples.py
++++ b/tests/test_doc_examples.py
+@@ -42,3 +42,5 @@ def test_doc_example(example):
+     """
+     with cd(example.parent):
+         runpy.run_path(str(example))
++    from lxml import etree
++    etree.set_default_parser(parser=etree.XMLParser())
diff --git a/dev-python/xmlsec/metadata.xml b/dev-python/xmlsec/metadata.xml
new file mode 100644
index 000000000..c75425b41
--- /dev/null
+++ b/dev-python/xmlsec/metadata.xml
@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE pkgmetadata SYSTEM "https://www.gentoo.org/dtd/metadata.dtd">
+<pkgmetadata>
+	<maintainer type="person">
+		<email>chutzpah@gentoo.org</email>
+		<name>Patrick McLean</name>
+	</maintainer>
+	<maintainer type="project">
+		<email>python@gentoo.org</email>
+		<name>Python</name>
+	</maintainer>
+	<upstream>
+		<remote-id type="github">xmlsec/python-xmlsec</remote-id>
+		<remote-id type="pypi">xmlsec</remote-id>
+	</upstream>
+</pkgmetadata>
diff --git a/dev-python/xmlsec/xmlsec-1.3.12-r3.ebuild b/dev-python/xmlsec/xmlsec-1.3.12-r3.ebuild
new file mode 100644
index 000000000..b85f07eb2
--- /dev/null
+++ b/dev-python/xmlsec/xmlsec-1.3.12-r3.ebuild
@@ -0,0 +1,58 @@
+# Copyright 2021-2023 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+DISTUTILS_EXT=1
+DISTUTILS_USE_PEP517=setuptools
+PYTHON_COMPAT=( python3_{10..12} )
+
+inherit distutils-r1
+
+MY_P=python-xmlsec-${PV}
+DESCRIPTION="Python bindings for the XML Security Library"
+HOMEPAGE="
+	https://github.com/xmlsec/python-xmlsec/
+	https://pypi.org/project/xmlsec/
+"
+SRC_URI="
+	https://github.com/xmlsec/python-xmlsec/archive/${PV}.tar.gz
+		-> ${MY_P}.gh.tar.gz
+"
+S=${WORKDIR}/${MY_P}
+
+LICENSE="MIT"
+SLOT="0"
+KEYWORDS="amd64 ~ppc64 x86"
+
+# Doesn't yet support xmlsec-1.3.0: https://github.com/xmlsec/python-xmlsec/issues/252
+RDEPEND="
+	<dev-libs/xmlsec-1.3.0:=[openssl]
+	dev-python/lxml[${PYTHON_USEDEP}]
+"
+DEPEND="${RDEPEND}"
+BDEPEND="
+	dev-python/pkgconfig[${PYTHON_USEDEP}]
+	dev-python/setuptools-scm[${PYTHON_USEDEP}]
+	dev-python/wheel[${PYTHON_USEDEP}]
+	test? (
+		dev-python/hypothesis[${PYTHON_USEDEP}]
+	)
+"
+
+PATCHES=(
+	"${FILESDIR}/${PN}-1.3.11-fix-xml-testfail.patch"
+)
+
+EPYTEST_DESELECT=(
+	# Fragile based on black version?
+	tests/test_type_stubs.py::test_xmlsec_constants_stub
+
+	# Broken with xmlsec-1.2.36+.
+	# https://github.com/xmlsec/python-xmlsec/issues/244
+	tests/test_ds.py::TestSignContext::test_sign_case5
+)
+
+distutils_enable_tests pytest
+
+export SETUPTOOLS_SCM_PRETEND_VERSION=${PV}