Dion O' Cuinneagain (born 24 May 1972, Cape Town, South Africa) is a former rugby union player who represented both South Africa and Ireland. Since retiring as a rugby player, O' Cuinneagain has worked as a doctor and as a rugby coach.

O' Cuinneagain was born and raised in Cape Town. His father, Connell, was a dentist who came from County Dublin, Ireland. The O' Cuinneagain family originally came from Enniscorthy in County Wexford. His mother was a nurse who came from Lancashire.