Gary O'Donnell (born 6 January 1988) is an Irish sportsperson, who plays inter-county Gaelic football for Galway. He is a first cousin of double All-Ireland-winning former Galway footballer and two-time All Star Jarlath Fallon. O'Donnell's parents are both from County Mayo and he has uncles who have played football for that county at a number of levels.^[1]

O'Donnell, who first played football with St Colman's, Gort, also played hurling in his youth and was on the same under-age teams as later Galway senior inter-county players Aidan Harte and Greg Lally. Gort's football team disbanded in 2009 and O'Donnell moved to Tuam Stars, as it was the club his cousins, the Fallons, played for.^[1]

Having been an unused substitute in Galway's 2008 Connacht final victory over Mayo,^[2] O'Donnell made his inter-county debut with in 2009. In 2016, O'Donnell was named Galway captain by Kevin Walsh, having previously captained the side on occasions when Paul Conroy wasn't available.^[3] On 17 July 2016, Galway won the Connacht Championship, and O'Donnell became the first Galway player since Pádraic Joyce in 2008 to receive the J. J. Nestor Cup.^[4][5]