diff --git a/tox.ini b/tox.ini
index 4c1e972a..46ffe70f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -72,6 +72,7 @@ deps =
     psycopg[binary]
     pytest<8.2.0
     pytest-mock
+    juju{env:LIBJUJU_VERSION_SPECIFIER:==3.6.1.0}
     coverage[toml]
     -r {tox_root}/requirements.txt
 commands =