diff --git a/debian/build_virtualenv b/debian/build_virtualenv
index e691163619..71d50a43ce 100755
--- a/debian/build_virtualenv
+++ b/debian/build_virtualenv
@@ -43,7 +43,8 @@ dh_virtualenv \
     --preinstall="wheel" \
     --extra-pip-arg="--no-cache-dir" \
     --extra-pip-arg="--compile" \
-    --extras="all,systemd,test"
+    --extras="all,systemd,test" \
+    --requirements="requirements.txt"
 
 PACKAGE_BUILD_DIR="debian/matrix-synapse-py3"
 VIRTUALENV_DIR="${PACKAGE_BUILD_DIR}${DH_VIRTUALENV_INSTALL_ROOT}/matrix-synapse"