Alan G. Cairns (b. August 12, 1940) is a Bible teacher, retired pastor, and author. A native of Belfast, Northern Ireland, he was converted to Christianity through The Salvation Army. He joined the nascent Free Presbyterian Church of Ulster as a teenager. After working for an insurance brokerage in Belfast for two years, he was called to the ministry and attended the Theological Hall of his denomination.
Cairns became pastor of Free Presbyterian churches in Dunmurry and then Ballymoney. In 1973 he began a radio ministry, "Let the Bible Speak", at first broadcasting on a single station on the Isle of Man. (By 2010, the programs were heard on more than a dozen stations in North America, India, Africa, and China.) Simultaneously, Cairns became professor of systematic theology at the Theological Hall.
In 1978, while visiting relatives in the United States, Cairns supplied the pulpit of Faith Free Presbyterian Church in Greenville, South Carolina, the first church in the United States to associate itself with the Ulster denomination. Asked to serve as pastor, Cairns at first declined, then accepted a formal call in 1980. In Greenville, Cairns founded Geneva Reformed Seminary, which today serves as the seminary for the Free Presbyterian Church of North America and has trained most of its clergy. Cairns adapted and published many of his sermon series as books, as well as edited a Dictionary of Theological Terms written from a Reformed perspective. In 2007, Cairns became pastor emeritus, and in 2009, he retired to Ballymoney, Northern Ireland.