diff --git a/changelog.d/12449.misc b/changelog.d/12449.misc
new file mode 100644
index 000000000..03e08aace
--- /dev/null
+++ b/changelog.d/12449.misc
@@ -0,0 +1 @@
+Use `poetry` to manage the virtualenv in debian packages.
diff --git a/debian/build_virtualenv b/debian/build_virtualenv
index e69116361..b06879259 100755
--- a/debian/build_virtualenv
+++ b/debian/build_virtualenv
@@ -30,9 +30,19 @@ case $(dpkg-architecture -q DEB_HOST_ARCH) in
         ;;
 esac
 
-# Use --builtin-venv to use the better `venv` module from CPython 3.4+ rather
-# than the 2/3 compatible `virtualenv`.
+# Manually install Poetry and export a pip-compatible `requirements.txt`
+# We need a Poetry pre-release as the export command is buggy in < 1.2
+TEMP_VENV="$(mktemp -d)"
+python3 -m venv "$TEMP_VENV"
+source "$TEMP_VENV/bin/activate"
+pip install -U pip
+pip install poetry==1.2.0b1
+poetry export --extras all --extras test -o exported_requirements.txt
+deactivate
+rm -rf "$TEMP_VENV"
 
+# Use --no-deps to only install pinned versions in exported_requirements.txt,
+# and to avoid https://github.com/pypa/pip/issues/9644
 dh_virtualenv \
     --install-suffix "matrix-synapse" \
     --builtin-venv \
@@ -41,9 +51,11 @@ dh_virtualenv \
     --preinstall="lxml" \
     --preinstall="mock" \
     --preinstall="wheel" \
+    --extra-pip-arg="--no-deps" \
     --extra-pip-arg="--no-cache-dir" \
     --extra-pip-arg="--compile" \
-    --extras="all,systemd,test"
+    --extras="all,systemd,test" \
+    --requirements="exported_requirements.txt"
 
 PACKAGE_BUILD_DIR="debian/matrix-synapse-py3"
 VIRTUALENV_DIR="${PACKAGE_BUILD_DIR}${DH_VIRTUALENV_INSTALL_ROOT}/matrix-synapse"
diff --git a/debian/changelog b/debian/changelog
index 67215aa08..fdbc92df6 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+matrix-synapse-py3 (1.58.0+nmu1) UNRELEASED; urgency=medium
+
+  * Non-maintainer upload.
+  * Use poetry to manage the bundled virtualenv included with this package.
+
+ -- Synapse Packaging Team <packages@matrix.org>  Wed, 30 Mar 2022 12:21:43 +0100
+
 matrix-synapse-py3 (1.57.0~rc1) stable; urgency=medium
 
   * New synapse release 1.57.0~rc1.
diff --git a/debian/clean b/debian/clean
new file mode 100644
index 000000000..d488f298d
--- /dev/null
+++ b/debian/clean
@@ -0,0 +1 @@
+exported_requirements.txt