Olenia (Greek: Ωλενία) is a former municipality in Achaea, West Greece, Greece.
Since the 2011 local government reform it is part of the municipality West Achaea, of which it is a municipal unit.
The seat of the municipality was in Lousika.
The municipality is named after the ancient Achaean town Olenus.
The municipal unit Olenia is subdivided into the following communities (constituent villages in brackets): This Western Greece location article is a stub.