diff --git a/pyproject.toml b/pyproject.toml
index 446fd1bf1..eaba32ef1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -49,7 +49,7 @@ dependencies = [
   "ipython",
   "meshio",
   "networkx>=2.8.2",
-  "numpy>=1.20",
+  "numpy>=1.20",<2,
   "pandas>=1.5",
   "pint>=0.18",
   "pint-xarray>=0.3",