diff --git a/noxfile.py b/noxfile.py
index 28142d8..e88385e 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -83,6 +83,9 @@ def install(session, group):
         run(session, "uv pip install --system torch")
         run(session, "uv pip install --system tiledbsoma")
         run(session, "uv pip install --system wetlab")
+        run(
+            session, "uv pip install --system numpy<2"
+        )  # https://github.com/scverse/pytometry/issues/80
     elif group == "by_registry":
         extras += ",zarr,jupyter"
         run(