Leo O'Brien may refer to:
Leo O'Brien (actor) (1970–2012), American television and film actor Leo O'Brien (cricketer) (1907–1997), Australian cricketer Leo F. O'Brien (1924-1968), American politician, member of the Illinois House of Representatives Leo P. O'Brien (1893–1968), American politician, member of the Wisconsin State Senate Leo W. O'Brien (1900–1982), American politician, Representative from New York