diff --git a/requirements.txt b/requirements.txt
index c56855e..15759be 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,3 @@
 SimpleITK >= 2.0.0
-numpy
+numpy<2.0.0 # scikkit-learn does not provide a maximum version for numpy
 scikit-learn == 1.3.0