| Oiartzun | |
| Settlement Type: | Municipality |
| Pushpin Map: | Spain Basque Country |
| Pushpin Map Caption: | Location of Oiartzun within the Basque Autonomous Community |
| Subdivision Type: | Country |
| Subdivision Type1: | Autonomous community |
| Subdivision Type2: | Province |
| Subdivision Name2: | Gipuzkoa |
| Subdivision Type3: | Eskualdea |
| Subdivision Name3: | Oarsoaldea |
| Coordinates: | 43.2986°N -1.8611°W |
| Area Total Km2: | 59.71 |
| Established Title: | Founded |
| Population Demonym: | Basque: oiartzuar Spanish; Castilian: oyarsonense |
| Population Density Km2: | auto |
| Blank Name Sec1: | Official language(s) |
| Timezone: | CET |
| Utc Offset: | +1 |
| Timezone Dst: | CEST |
| Utc Offset Dst: | +2 |
| Postal Code Type: | Postal code |
| Postal Code: | 20180 |
| Area Code Type: | Dialing code |
| Leader Title: | Mayor |
| Leader Name: | Joana Mendiburu Garaiar |
| Leader Party: | EH Bildu |
Oiartzun (Basque: Oiartzun, Spanish; Castilian: Oyarzun) is a town and municipality located in the Basque Country, in the province of Gipuzkoa lying at the foot of the massif Aiako Harria (Peñas de Aya in Spanish).
See main article: article and Oiasso. The name traces back to Oiasso or Oiarso, a Roman town closely connected to the Arditurri mines in the massif of Aiako Harria, which contained large amounts of silver and copper. However, it has been pinpointed to the current border town of Irun, so the name may have referred to the whole area.
A river bearing the same name meanders through the meadows and neighbourhoods of this sparse municipality. That is one of its main features, it is scattered in different quarters across the valley. Elizalde lies on a prominence and it is the central nucleus of the town, with the main church San Esteban and town hall being located there. At the foot of Elizalde lies Altzibar by the Oiartzun River. Ugaldetxo developed into an urban built-up area surrounded by industrial estates near the AP-8 motorway, while the rest of the neighbourhoods have hung onto their rural and picturesque landscape to a large extent.
Alfonso VIII of Castile chartered it as town but it took some decades before its independence from Orereta was total.
The town's football club, Oiartzun KE, plays at Karla Lekuona. The women's side has competed in the highest division of Spanish football, making Oiartzun one of the smallest towns in the country home to a top-flight club.
Oiartzun is twinned with:
