Dyer Ball (June 3, 1796 – March 27, 1866) was an American missionary and medical doctor in China. Born in West Boylston, Massachusetts , Dyer Ball studied at Phillips Academy and at Yale College for two years. He graduate from Union College, New York, in 1826, and then studied Theology at Yale and Andover Theological Seminary. He received his licence to preach in 1828, one year after marrying Lucy Mills. After being ordained in 1831, he became an agent of the American Home Missionary Society in 1833, and settled in Florida, where he taught, among other places, at St. Augustine school, Fla., and among the local African-American community. Meanwhile, as his appointment to a mission abroad was delayed due to financial circumstances, he also received a medical degree from a medical institution in Charleston, South Carolina, in 1837, and learnt Chinese.
He was sent to Singapore by the American Board of Commissioners for Foreign Missions on 25 May 1838, and remained there until 1841, when he departed for Macao due to his wife's ailing health. He then moved to Hong Kong in 1843, where his wife died, and to Canton, China, in 1845, where he settled permanently. He remarried in 1846, his new wife, Isabella Robertson, being a missionary from Scotland. His work focused mainly on performing missionary work and preaching. He ran a boys' school and opened a publishing house, where he published Chinese literature, religious tracts and a popular Chinese almanac. He also used his medical experience to help the local population. Dyer Ball died in Canton in 1866. He is buried at the Mission Cemetery in Lienchow.