diff --git a/tox.ini b/tox.ini
index 1f8930004..135945a5d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -87,6 +87,7 @@ deps =
     pytest
     coverage
     hypothesis<=6.72.0
+    setuptools
 commands = pytest tests/test_B1855.py tests/test_B1855_9yr.py tests/test_new_observatories.py