:Olenia

{{Infobox Greek Dimos

|name = Olenia

|name_local = Ωλενία

|type = municipal unit

|image_map = DE Olenias.svg

|map_caption = Location within the regional unit

|periph = West Greece

|periphunit = Achaea

|municipality = West Achaea

|pop_municunit = 4303

|population_as_of = 2021

|area_municunit = 189.5

|elevation = 163

|coordinates = {{coord|38|6|N|21|35|E|format=dms|display=inline,title}}

|postal_code =

|area_code =

|licence = ΑΧ

|website =

|image_skyline =

|caption_skyline =

|city_flag =

|city_seal =

|districts =

}}

File:Fragma Asteriou i Fragma Parapeirou, Achaia (Asteri or Parapiros Dam Lake, Achaia, Greece).jpg

Olenia ({{langx|el|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.{{Cite web|url=http://www.et.gr/idocs-nph/search/pdfViewerForm.html?args=5C7QrtC22wGYK2xFpSwMnXdtvSoClrL81-32jgAMSfbnMRVjyfnPUeJInJ48_97uHrMts-zFzeyCiBSQOpYnT00MHhcXFRTsb2fGphpq4MKX2ZkaHobySNnvZCNHXvYVvlf80XevW0Q.|title=ΦΕΚ B 1292/2010, Kallikratis reform municipalities|language=el|publisher=Government Gazette}} The municipal unit has an area of 189.534 km².{{cite web|url=http://dlib.statistics.gr/Book/GRESYE_02_0101_00098%20.pdf|publisher=National Statistical Service of Greece|title=Population & housing census 2001 (incl. area and average elevation)|language=el}} Population 4,303 (2021). The seat of the municipality was in Lousika. The municipality is named after the ancient Achaean town Olenus.