diff --git a/conda/meta.yaml b/conda/meta.yaml
index b8bab4a7..7d524478 100644
--- a/conda/meta.yaml
+++ b/conda/meta.yaml
@@ -24,6 +24,7 @@ test:
   requires:
     - ipympl
     - ipywidgets
+    - mpltoolbox
     - pandas
     - pytest
     - python-graphviz