diff --git a/spack-environment/dev/spack.yaml b/spack-environment/dev/spack.yaml
index 20b3f312fbe989f7492c177babcd7aba68137515..3736897b6d9b4da33216e93ccde8a9fa0dab59c3 100644
--- a/spack-environment/dev/spack.yaml
+++ b/spack-environment/dev/spack.yaml
@@ -66,6 +66,7 @@ spack:
     - py-mplhep
     - py-htgettoken
     - py-numpy
+    - py-onnx
     - py-onnxruntime
     - py-pandas
     - py-pip