Thomas OâÂÂBrien, Tom OâÂÂBrien, or Tommy O'Brien may refer to:
Politicians
Sportspeople
- Thomas O'Brien (footballer) (born 1991), Scottish footballer
- Tom O'Brien (American football) (born 1948), former American college football coach at NC State
- Tom O'Brien (footballer, born 1889) (1889âÂÂ1963), Australian rules footballer for University
- Tom O'Brien (footballer, born 1904) (1904âÂÂ1983), Australian rules footballer for Melbourne
- Tom O'Brien (jockey) (born 1986), Irish jockey
- Tom O'Brien (outfielder) (1873âÂÂ1901), Major League Baseball outfielder/infielder
- Tom O'Brien (second baseman) (1860âÂÂ1921), baseball player
- Tommy O'Brien (baseball) (1918âÂÂ1978), Major League Baseball outfielder
- Tommy O'Brien (rugby union), Irish rugby union player
- Tommy O'Brien (basketball), American basketball player
Others
- Thomas O'Brien (bishop) (1792âÂÂ1874), Church of Ireland bishop of Ossory, Ferns, and Leighlin
- Thomas O'Brien (interior designer) (born 1961), American designer
- Thomas D. O'Brien (1859âÂÂ1935), co-founder of William Mitchell College of Law
- Thomas J. O'Brien (bishop) (1935-2018), bishop of Phoenix, 1982âÂÂ2003
- Thomas W. O'Brien (1859âÂÂ1916), Canadian entrepreneur and pioneer
- Thomas Alexander O'Brien (1888âÂÂ1948), New Zealand cinema owner and entrepreneur
- Thomas Enraght O'Brien (1827âÂÂ1896), lord lieutenant of Limerick
- Tom O'Brien (actor, born 1890) (1890-1947), American film actor
- Tom O'Brien (actor) (born 1965), American film actor
- Tom O'Brien (swindler) (1851âÂÂ1904), American confidence man and swindler