diff --git a/pyproject.toml b/pyproject.toml
index b1f36d949..f81612231 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -17,6 +17,7 @@ dependencies = [
     'aind-data-schema-models>=5.4.1,<6',
     'pydantic>=2.7, <2.12',
     'pydantic-extra-types',
+    'tzdata',
 ]
 
 [project.optional-dependencies]