diff --git a/pyproject.toml b/pyproject.toml
index 569a7b3..8aeb7f5 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -41,6 +41,7 @@ dependencies = [
     "pympler>=1.0.0",
     "tqdm>=4.0.0",
     "numpy>=1.20.0",
+    "oa-atomacos>=3.2.0; sys_platform == 'darwin'",
 ]
 
 [project.optional-dependencies]