diff --git a/doc/source/groupby.rst b/doc/source/groupby.rst
index 02d4a924a92fc..5d82b4f95487f 100644
--- a/doc/source/groupby.rst
+++ b/doc/source/groupby.rst
@@ -747,7 +747,7 @@ The dimension of the returned result can also change:
 .. ipython:: python
 
     def f(x):
-      return pd.Series([ x, x**2 ], index = ['x', 'x^s'])
+      return pd.Series([ x, x**2 ], index = ['x', 'x^2'])
     s = pd.Series(np.random.rand(5))
     s
     s.apply(f)