| Ona One | |
| Pushpin Map: | Vestland#Norway |
| Pushpin Label: | Ona |
| Pushpin Label Position: | top |
| Pushpin Map Caption: | Location of the island |
| Location: | Vestland, Norway |
| Coordinates: | 60.5545°N 4.8449°W |
| Area Km2: | 6.8 |
| Length Km: | 4.5 |
| Width Km: | 2.5 |
| Elevation M: | 53 |
| Highest Mount: | Vareidet |
| Country: | Norway |
| Country Admin Divisions Title: | County |
| Country Admin Divisions: | Vestland |
| Country Admin Divisions Title 1: | Municipality |
| Country Admin Divisions 1: | Øygarden Municipality |
| Population: | 230 |
| Population As Of: | 2001 |
Ona or One (sometimes Oøy or Oni) is an island in Øygarden municipality in Vestland county, Norway. The 6.8km2 island lies in the Øygarden archipelago just north of the island of Blomøyna and south of Alvøyna. The Hjeltefjorden lies east of the island and the North Sea and some smaller island lie to the west. The southern portion of the island of Ona is dominated by the Kollsnes natural gas processing facility. The island is low, rocky, and barren, with its highest point being the 53m (174feet) tall Vareidet hill.[1]