Oscar Edgar Onley (born 13 October 2002) is a Scottish cyclist, who currently rides for UCI WorldTeam Team dsm–firmenich PostNL.

After spending two seasons with Development Team DSM, he joined UCI WorldTeam Team dsm–firmenich PostNL in 2023, having signed a five-year contract with the team in late 2022. In 2023, he competed in his first Grand Tour, the Vuelta a España, where he was part of the winning team on the stage one team time trial. The following January, Onley took his first professional win in an uphill finish on stage five of the Tour Down Under, ultimately finishing fourth overall.