Peter O'Brien may refer to:
Sportsmen Peter O'Brien (outfielder) (born 1990), MLB outfielder, 2015–present Pete O'Brien (1900s second baseman) (1877–1917), MLB second baseman, 1901–1907 Pete O'Brien (1890s second baseman) (1867–1937), MLB second baseman, 1887–1890 Pete O'Brien (first baseman) (born 1958), MLB first baseman, 1982–1993 Peter O'Brien (Gaelic footballer), Gaelic football goalkeeper Peter O'Brien (rugby league) (1928–2016), Australian rugby league footballer Peter O'Brien (hurler) (born 1987), Irish hurler Others Peter O'Brien, 1st Baron O'Brien (1842–1914), also known as Sir Peter O'Brien, Irish lawyer and judge Peter O'Brien (actor) (born 1960), Australian actor Peter O'Brien (theologian) (born 1935), Australian New Testament scholar Peter O'Brien (Medal of Honor) (1842–1898), American Civil War soldier and Medal of Honor recipient James O'Brien (New Zealand politician) (Peter James O'Brien, 1874–1947)
See also Peter O'Brian (disambiguation)