William John Beattie (born 21 September 1942) is a former minister of religion and Unionist politician in Northern Ireland. Beattie grew up in Ballymena. In 1965, he became a student minister at the Dunmurry Free Presbyterian Church, and in 1967 he became a full minister in the Church, led by Ian Paisley. He also joined Paisley's Protestant Unionist Party (PUP), and became the deputy leader. Beattie stood for Belfast North in the 1970 general election, but came a distant third, behind the Ulster Unionist and Labour candidates.