Adin Ballou (April 23, 1803 – August 5, 1890) was an American prominent proponent of pacifism, socialism and abolitionism, and the founder of the Hopedale Community. Through his long career as a Universalist, and then Unitarian minister, he tirelessly sought social reform through his radical Christian and socialist views. His writings drew the admiration of Leo Tolstoy, who sponsored Russian translations of some of Ballou's works.
Ballou was born in 1803 on a farm in Cumberland, Rhode Island to Ariel and Elida (née Tower) Ballou. He was raised a Six-Principle Baptist until 1813 when his family was converted in a Christian Connexion revival.
Ballou married Abigail Sayles in early 1822, the same year he converted to Universalism. His wife died in 1829, shortly after giving birth to a daughter. Later that year, Ballou suffered a life-threatening illness. He was nursed back to health by Lucy Hunt, whom he married a few months later. Hosea Ballou II performed the ceremony. Of four children born to Ballou, only Abbie Ballou reached adulthood.
Ballou was a prominent local historian for Milford, writing one of the earliest complete history's of the town in 1882, "History of the town of Milford, Worcester county, Massachusetts, from its first settlement to 1881".
Ballou died in Hopedale in 1890. Lucy Ballou died the following year.
Ballou traveled around New England lecturing and debating on Practical Christianity, Christian nonresistance, abolition, temperance, and other social issues.