Cyrus Byington (March 11, 1793 – December 31, 1868) was a Christian missionary from Massachusetts who began working with the Choctaw in Mississippi in 1821. Although he had been trained as a lawyer, he abandoned law as a career and became a minister affiliated with the American Board of Commissioners for Foreign Missions. During this period he learned the Choctaw language, which was then entirely unwritten. He also began to develop a Choctaw orthography.