diff --git a/pyproject.toml b/pyproject.toml
index 278a8c9..8cf6de1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,5 +1,5 @@
 [build-system]
-requires = ["setuptools>=49.2.1", "torch >= 2.0.0", "tqdm", "matplotlib"]
+requires = ["setuptools>=49.2.1", "torch >= 2.0.0", "tqdm", "matplotlib", "numpy"]
 build-backend = "setuptools.build_meta"
 [tool.setuptools]
 packages = ["ProbabilisticDiffusion"]