diff --git a/wheelhouse.txt b/wheelhouse.txt
index bd63690..e80d0d2 100644
--- a/wheelhouse.txt
+++ b/wheelhouse.txt
@@ -1,5 +1,11 @@
 # charmhelpers.contrib.openstack.cert_utils charms with certificates relation
-dnspython
+
+# NOTE(lourot): dnspython 2.0.0 dropped py3.5 support. We can't use environment
+# markers like "python_version < '3.6'" here because they get matched at build
+# time against the interpreter used to build the charm, not against the target
+# interpreter at install time.
+dnspython<2.0.0
+
 # charmhelpers.contrib.network all
 netifaces>=0.10.4
 # charmhelpers.contrib.openstack.context all