diff --git a/intake_esm/cat.py b/intake_esm/cat.py
index 8df7f6e2..d115d85a 100644
--- a/intake_esm/cat.py
+++ b/intake_esm/cat.py
@@ -111,7 +111,7 @@ class ESMCatalogModel(pydantic.BaseModel):
     esmcat_version: pydantic.StrictStr
     attributes: typing.List[Attribute]
     assets: Assets
-    aggregation_control: AggregationControl
+    aggregation_control: typing.Optional[AggregationControl] = None
     id: typing.Optional[str] = ''
     catalog_dict: typing.Optional[typing.List[typing.Dict]] = None
     catalog_file: pydantic.StrictStr = None
diff --git a/tests/test_cat.py b/tests/test_cat.py
index 875a1eef..6726c31d 100644
--- a/tests/test_cat.py
+++ b/tests/test_cat.py
@@ -12,6 +12,7 @@
     multi_variable_cat,
     sample_df,
     sample_esmcat_data,
+    sample_esmcat_data_without_agg,
     zarr_cat_aws_cesm,
     zarr_cat_pangeo_cmip6,
 )
@@ -54,12 +55,15 @@ def test_esmcatmodel_load(file):
     assert isinstance(cat.has_multiple_variable_assets, bool)
 
 
-def test_esmcatmodel_from_dict():
-    cat = ESMCatalogModel.from_dict({'esmcat': sample_esmcat_data, 'df': sample_df})
+@pytest.mark.parametrize(
+    'esmcat_data',
+    [sample_esmcat_data, sample_esmcat_data_without_agg],
+)
+def test_esmcatmodel_from_dict(esmcat_data):
+    cat = ESMCatalogModel.from_dict({'esmcat': esmcat_data, 'df': sample_df})
     assert isinstance(cat, ESMCatalogModel)
     assert isinstance(cat.df, pd.DataFrame)
     assert isinstance(cat.columns_with_iterables, set)
-    assert isinstance(cat.has_multiple_variable_assets, bool)
 
 
 @pytest.mark.parametrize(