diff --git a/docs/tutorials/simple_fitting.ipynb b/docs/tutorials/simple_fitting.ipynb
index 373cf761..ca79b521 100644
--- a/docs/tutorials/simple_fitting.ipynb
+++ b/docs/tutorials/simple_fitting.ipynb
@@ -341,7 +341,7 @@
     "# Roughnesses\n",
     "sio2_layer.roughness.bounds = (1, 15)\n",
     "film_layer.roughness.bounds = (1, 15)\n",
-    "superphase.roughness.bounds = (1, 15)\n",
+    "subphase.roughness.bounds = (1, 15)\n",
     "# Scattering length density\n",
     "film_layer.material.sld.bounds = (0.1, 3)"
    ]