Duncan O'Mahony [oh-MAH-nee] (b. June 29, 1976 in Kilkenny, Republic of Ireland) is a former Canadian football punter and placekicker who most recently played for the BC Lions of the CFL.
Despite being born in Ireland and having lived in Australia and Newfoundland as a child, O'Mahony is considered a non-import by the CFL, as he and his family settled in Abbotsford, British Columbia when he was a teenager.
After his college career, O'Mahony joined the Calgary Stampeders for the 2001 CFL season, initially as a punter while Mark McLoughlin handled the placekicking duties.
However, a lack of accuracy put him in the fans' doghouse quickly, and McLoughlin was lured out of retirement at the end of the 2003 CFL season so O'Mahony could return to full-time punting.
O'Mahony had an adequate 2004 kicking two 40+ yard field goals in the western conference final against Saskatchewan to win the game, but his performance in 2005 was such that McLoughlin was again lured out of retirement to relieve him of his placekicking duties at the end of the year and the playoffs.