diff --git a/sklearn/isotonic.py b/sklearn/isotonic.py
index 24d62dfe1c69a..aa1521ab697d0 100644
--- a/sklearn/isotonic.py
+++ b/sklearn/isotonic.py
@@ -109,7 +109,7 @@ def isotonic_regression(
 
     Returns
     -------
-    y_ : list of floats
+    y_ : ndarray of shape (n_samples,)
         Isotonic fit of y.
 
     References