diff --git a/jenkins-dendron-haproxy-postgres.sh b/jenkins-dendron-haproxy-postgres.sh
index d64b2d2c9..07979bf8b 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 37ae746f4..3b932fe34 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 f2ca8ccdf..1afb73639 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 84613d979..baf4713a0 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 \