| John L. Dagg | |
| Birth Date: | 14 February 1794 |
| Birth Place: | Middleburg, Virginia |
| Death Place: | Hayneville, Lowndes County, Alabama |
| Resting Place: | Hayneville Cemetery, Hayneville, Alabama |
| Occupation: | Baptist clergyman, author, and president of Mercer University |
John Leadley Dagg (1794–1884), born in Loudoun County, Virginia was an American Baptist theologian.
Dagg had a limited education, was near-blind, and physically disabled.[1] He converted to Christianity at age 15 and served briefly in the War of 1812.[2] Dagg was baptized in 1812 then studied medicine for three years. He was ordained as a minister in November 1817 and eventually served as the pastor of the Fifth Baptist Church in Philadelphia for nine years.[3] He then moved to Tuscaloosa, Alabama and served as the president of the Alabama Female Athenaeum for eight years. Dagg left Tuscaloosa in January 1844 to become president of Mercer University.[3] He served as president of Mercer until 1854, when his failing health forced him to retire.[2] After retirement, Dagg authored four books. The first, Manual of Theology, was written in 1857 and was the first systematic theology written by a Baptist in America.[2] His additional books included Treatise on Church Order (1858), Elements of Moral Science (1859), and Evidences of Christianity (1869).[3] Dagg moved to Alabama to live near his daughter, where he died in Hayneville in 1884.[3]