diff --git a/jenkins-dendron-haproxy-postgres.sh b/jenkins-dendron-haproxy-postgres.sh
index d64b2d2c9de0368b6aebb55a847c7450bb15aca6..07979bf8b825e4035c50f3b51e839c9518c3365c 100755
--- a/jenkins-dendron-haproxy-postgres.sh
+++ b/jenkins-dendron-haproxy-postgres.sh
@@ -17,6 +17,7 @@ export HAPROXY_BIN=/home/haproxy/haproxy-1.6.11/haproxy
 ./sytest/jenkins/prep_sytest_for_postgres.sh
 
 ./sytest/jenkins/install_and_run.sh \
+    --python $WORKSPACE/.tox/py27/bin/python \
     --synapse-directory $WORKSPACE \
     --dendron $WORKSPACE/dendron/bin/dendron \
     --haproxy \
diff --git a/jenkins-dendron-postgres.sh b/jenkins-dendron-postgres.sh
index 37ae746f4bb48c56b8f83e07f3b4cd68b1a48497..3b932fe3402390c7e4c3b7e1e886d521ac7a43ca 100755
--- a/jenkins-dendron-postgres.sh
+++ b/jenkins-dendron-postgres.sh
@@ -15,5 +15,6 @@ export SYNAPSE_CACHE_FACTOR=1
 ./sytest/jenkins/prep_sytest_for_postgres.sh
 
 ./sytest/jenkins/install_and_run.sh \
+    --python $WORKSPACE/.tox/py27/bin/python \
     --synapse-directory $WORKSPACE \
     --dendron $WORKSPACE/dendron/bin/dendron \
diff --git a/jenkins-postgres.sh b/jenkins-postgres.sh
index f2ca8ccdff30cb06761b4b44e4e868c181bd63cf..1afb736394e4b0bea7b5a923a571eaa4c0094ba9 100755
--- a/jenkins-postgres.sh
+++ b/jenkins-postgres.sh
@@ -14,4 +14,5 @@ export SYNAPSE_CACHE_FACTOR=1
 ./sytest/jenkins/prep_sytest_for_postgres.sh
 
 ./sytest/jenkins/install_and_run.sh \
+    --python $WORKSPACE/.tox/py27/bin/python \
     --synapse-directory $WORKSPACE \
diff --git a/jenkins-sqlite.sh b/jenkins-sqlite.sh
index 84613d979c665aead6d1e45a03a1d2c419ed2182..baf4713a01d680ed23e66987d9820653185184f5 100755
--- a/jenkins-sqlite.sh
+++ b/jenkins-sqlite.sh
@@ -12,4 +12,5 @@ export SYNAPSE_CACHE_FACTOR=1
 ./jenkins/clone.sh sytest https://github.com/matrix-org/sytest.git
 
 ./sytest/jenkins/install_and_run.sh \
+    --python $WORKSPACE/.tox/py27/bin/python \
     --synapse-directory $WORKSPACE \