diff --git a/pyproject.toml b/pyproject.toml
index 71e0390..02a31cb 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ urls = { Documentation = "https://automl.github.io/DEHB/", Github = "https://git
 name = "DEHB"
 version = "0.1.1"
 dependencies = [
-  "numpy>=1.18.2",
+  "numpy>=1.18.2,<2.0",
   "loguru>=0.5.3",
   "dask>=2.27.0",
   "distributed>=2.27.0",