diff --git a/pyproject.toml b/pyproject.toml
index 0fbf7608c4..9bb2ae9c3a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -35,7 +35,7 @@ classifiers = [
     "Topic :: Scientific/Engineering",
 ]
 dependencies = [
-    "numpy>=1.23.5",
+    "numpy>=1.23.5,<2.0.0",
     "scipy>=1.11.4",
     "casadi>=3.6.5",
     "xarray>=2022.6.0",