diff --git a/cds_migrator_kit/rdm/records/transform/mappers/vocabulary.py b/cds_migrator_kit/rdm/records/transform/mappers/vocabulary.py
index 8f52fe40..f711d155 100644
--- a/cds_migrator_kit/rdm/records/transform/mappers/vocabulary.py
+++ b/cds_migrator_kit/rdm/records/transform/mappers/vocabulary.py
@@ -54,9 +54,11 @@ def _load(filepath):
             if title and title.lower() != entry_id.lower():
                 lookup[title.lower()] = entry_id
 
+            # For now, I think this only supports one string value. If we make it support more in the future (e.g. via CSV) we
+            # will need to update this.
             entry_aliases = entry.get("props", {}).get("aliases")
-            for alias in entry_aliases or []:
-                lookup[alias.strip().lower()] = entry_id
+            if entry_aliases:
+                lookup[entry_aliases.strip().lower()] = entry_id
         return lookup
 
     def get(self, term, vocab_type):