Archibald Alexander (April 17, 1772 – October 22, 1851) was an American Presbyterian theologian and professor at the Princeton Theological Seminary. He served for 27 years as that institution's first principal from 1812 to 1840.
By the time he was 21 Alexander was a preacher of the Presbyterian Church. He was appointed the president of Hampden-Sydney College and from there was called to the Third Presbyterian Church of Philadelphia. The Princeton Theological Seminary was established at Princeton, New Jersey in 1812 and Alexander was appointed its first professor, inaugurated on August 12, 1812. In 1824, he helped to found the Chi Phi Society along with Robert Baird and Charles Hodge.
Samuel Miller became the second professor at the seminary and for 37 years Alexander and Miller were considered together as pillars of the Presbyterian Church in maintaining its doctrines. Charles Hodge, a famous student and successor of Alexander, named his son Archibald Alexander Hodge after his mentor.
His eldest son, James Waddel Alexander (1804-1859) was a Princeton graduate and Presbyterian minister. He wrote the life of his father, and edited his posthumous works.
His grandson, William Alexander, was an executive with Equitable Life Assurance Society, author, and founder of Pi Kappa Alpha Fraternity.