O'Neill
- Country: United States
- State: Nebraska
- Population: 3,631 (2016)
- Latitude: 42° 27.5' N (42.45778°)
- Longitude: 98° 38.9' W (-98.64759°)
- Elevation: 606 m/1,987 ft. above sea level
- Time zone: America/Chicago (UTC -06:00); DST observed (UTC -05:00)