diff --git a/docs/tutorial.rst b/docs/tutorial.rst
index 8f3849f..d171735 100644
--- a/docs/tutorial.rst
+++ b/docs/tutorial.rst
@@ -102,7 +102,7 @@ Changing geometrical and atmospheric parameters
 
 To change the zenith angle ::
 
-    mceq.set_zenith_deg(<zenith_angle_in_degrees>)
+    mceq.set_theta_deg(<zenith_angle_in_degrees>)
 
 Most geometries support angles between 0 (vertical) and 90 degrees.