diff --git a/setup.cfg b/setup.cfg
index 357b339b..9a2ed7e7 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -18,6 +18,7 @@ install_requires =
     jax>=0.4.12
     jaxlib>=0.4.12
     flowMC>=0.2.4
+    numpy>=1,<2
     ripplegw
     gwpy
     corner