John Dixon Long (September 26, 1817 – 1894) was a minister of the Methodist Episcopal Church and a leading U.S. abolitionist. His 1857 book, Pictures of Slavery in Church and State, was influential in abolitionist circles. Long was born in , Maryland to John W. Long, a slaveholder and former sea-captain. He credited his mother Sally Laws Henderson Long with inspiring his early antislavery sentiments. A devout member of the Methodist Episcopal Church, she died in 1828. Long's father died in 1834, leaving Long to support two sisters and brother. John Dixon Long died in Philadelphia in 1894.