Shay Brennan (May 6, 1937 - June 2000) was a English football player in the 1960s. He was a full back for Manchester United. He was excellent at moving the ball forward from defense.
His first game for the club came in 1958 against Sheffield Wednesday. He helped United to the 1965 and 1967 Division One championships, as well as the 1968 European Cup. Despite being born in England, he played internationally for Ireland because of the change in eligibility rules set forth by FIFA. He would retire from Manchester United in 1970 after playing 355 games and scoring 6 goals.
He was born in Manchester.