Captain Lawrence Percy Story Orr (16 September 1918 – 11 July 1990) was an Ulster Unionist politician in Northern Ireland.
He was Member of Parliament (MP) for South Down from 1950 until he retired at the October 1974 general election, preceding Enoch Powell.
He was later chairman of the Ulster Unionist MPs in the House of Commons from 1964 to 1974 and also Imperial Grand Master of the Orange Order.
He defended the influence of Orangemen in the UUP, saying they are "neither bigoted nor uncharitable ... we do not seek to injure or upbraid a man on account of his religious opinions ... and that they treated those who differed from them with all the common courtesies of a civilised community."
He married Jean Hughes and she bore five children, William, Mary, John, Robin and Christopher.