diff --git a/starsim/sim.py b/starsim/sim.py
index c69b0ff1..92fd3969 100644
--- a/starsim/sim.py
+++ b/starsim/sim.py
@@ -598,9 +598,9 @@ def plot(self, key=None, fig=None, style='fancy', show_data=True, show_skipped=F
 
             if key is not None:
                 if isinstance(key, str):
-                    flat = {k:v for k,v in flat.items() if (key in k)}
+                    flat = {k:v for k,v in flat.items() if (key.lower() in k)}
                 else:
-                    flat = {k:flat[k] for k in key}
+                    flat = {k.lower():flat[k.lower()] for k in key}
 
             # Get the figure
             if fig is None: