Páidí O'Brien (born 13 February 1984 in Cork, Ireland^[1]) is an Irish professional cyclist. He won the National Under-23 Road Race Championships twice, and in the senior National Road Race Championships, O'Brien has twice came second and third three times.

O'Brien was a member of the team time trial squad that won the opening stage of Vuelta a Extremadura in April 2008. As first of the team across the line,^[2] he wore the leader's jersey for the second stage. He lost nine seconds and the jersey went to team-mate Benny Deschrooder.^[3]