diff --git a/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py b/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py
index 168de44d..93a8ba69 100644
--- a/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py
+++ b/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py
@@ -1011,7 +1011,9 @@ def get_multi_indexes(
                     "column_names": row[3],
                     "unique": row[4],
                     "column_sorting": {
-                        col: order for col, order in zip(row[3], row[5])
+                        col: order.lower()
+                        for col, order in zip(row[3], row[5])
+                        if order is not None
                     },
                 }
                 row[0] = row[0] or None