diff --git a/pyproject.toml b/pyproject.toml
index c1603590e..6e6c0339d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,3 +1,3 @@
 [build-system]
-requires = ["setuptools", "wheel"]
+requires = ["setuptools", "wheel", "cython"]
 build-backend="setuptools.build_meta"