Justice O'Brien may refer to:
Charles H. O'Brien (1920–2007), associate justice of the Tennessee Supreme Court Denis O'Brien (politician) (1837–1909), judge of the New York Court of Appeals Henry X. O'Brien (1903/04–1990), associate justice of the Supreme Court of Pennsylvania James O'Brien (1830–1901), chief justice of the New Mexico Territorial Supreme Court John F. O'Brien (judge) (1874–1939), chief judge of the New York Court of Appeals Thomas D. O'Brien (1859–1935), associate justice of the Minnesota Supreme Court