diff --git a/setup.py b/setup.py
index 0198235..081710c 100644
--- a/setup.py
+++ b/setup.py
@@ -49,7 +49,7 @@
         test_suite="smact.tests.test",
         install_requires=[
             "scipy",
-            "numpy",
+            "numpy<2",
             "spglib",
             "pymatgen>=2024.2.20",
             "ase",