diff --git a/sklearn/semi_supervised/label_propagation.py b/sklearn/semi_supervised/label_propagation.py
index cacf51af242a4..0da5e3b128e2b 100644
--- a/sklearn/semi_supervised/label_propagation.py
+++ b/sklearn/semi_supervised/label_propagation.py
@@ -426,7 +426,7 @@ class LabelSpreading(BaseLabelPropagation):
       parameter for knn kernel
 
     alpha : float
-      Clamping factor. A value in [0, 1] that specifies the relative amount
+      Clamping factor. A value in (0, 1) that specifies the relative amount
       that an instance should adopt the information from its neighbors as
       opposed to its initial label.
       alpha=0 means keeping the initial label information; alpha=1 means