diff --git a/pyproject.toml b/pyproject.toml
index 4e680a8..2d919dd 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,8 @@ authors = [
 requires-python = '>=3.9'
 dependencies = [
     'brian2>=2.5.0.2,<2.6',
-    'setuptools>=61'
+    'setuptools>=61',
+    'numpy<2'
 ]
 dynamic = ["version", "readme"]
 description = 'An interface to use the GeNN framework as a device in Brian 2'