diff --git a/.github/workflows/conda/environment_all.yml b/.github/workflows/conda/environment_all.yml
index 5d8e21c5e..eac1ec0fa 100644
--- a/.github/workflows/conda/environment_all.yml
+++ b/.github/workflows/conda/environment_all.yml
@@ -4,7 +4,7 @@ channels:
 dependencies:
   - eigen
   - cmake
-  - numpy
+  - numpy<2.0
   - pkg-config
   - boost
   - ccache