diff --git a/pyproject.toml b/pyproject.toml
index a3e8cc944..b8d602eb0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -5,6 +5,6 @@ requires = ["setuptools>=42.0.0",
             "wheel",
             "oldest-supported-numpy",
             "cython==3.0.2",
-            "extension-helpers"]
+            "extension-helpers==1.*"]
 
 build-backend = 'setuptools.build_meta'