diff --git a/pyiceberg/catalog/__init__.py b/pyiceberg/catalog/__init__.py
index 01dd228efb..cf649ba7d6 100644
--- a/pyiceberg/catalog/__init__.py
+++ b/pyiceberg/catalog/__init__.py
@@ -252,7 +252,7 @@ def load_catalog(name: Optional[str] = None, **properties: Optional[str]) -> Cat
 
     catalog_type = None
     if provided_catalog_type and isinstance(provided_catalog_type, str):
-        catalog_type = CatalogType[provided_catalog_type.upper()]
+        catalog_type = CatalogType(provided_catalog_type.lower())
     elif not provided_catalog_type:
         catalog_type = infer_catalog_type(name, conf)
 
diff --git a/tests/catalog/test_base.py b/tests/catalog/test_base.py
index c00f4fde95..6e00bfec3a 100644
--- a/tests/catalog/test_base.py
+++ b/tests/catalog/test_base.py
@@ -88,6 +88,10 @@ def given_catalog_has_a_table(
     )
 
 
+def test_load_catalog_in_memory() -> None:
+    assert load_catalog("catalog", type="in-memory")
+
+
 def test_load_catalog_impl_not_full_path() -> None:
     with pytest.raises(ValueError) as exc_info:
         load_catalog("catalog", **{"py-catalog-impl": "CustomCatalog"})