diff --git a/tox.ini b/tox.ini
index 141512a..6dbc775 100644
--- a/tox.ini
+++ b/tox.ini
@@ -30,6 +30,7 @@ deps =
     oldest: orange-widget-base==4.19.0
     oldest: pandas==1.3
     oldest: numpy~=1.21.0
+    oldest: scipy~=1.9.0
     latest: git+https://github.com/biolab/orange3.git#egg=orange3
     latest: git+https://github.com/biolab/orange-canvas-core.git#egg=orange-canvas-core
     latest: git+https://github.com/biolab/orange-widget-base.git#egg=orange-widget-base