William Moseley Swain (May 12, 1809 in Manlius, New York – February 16, 1868 in Philadelphia, Pennsylvania) was an American journalist and businessman.
He was one of the founders and proprietors of the Philadelphia Public Ledger in 1836 (along with Arunah Shepherdson Abell and Azariah H. Simmons) and also served as editor. The paper was the first daily to establish a pony express, and one of the first to use the telegraph. In 1847, it was printed on the first rotary press ever built.
In May 1845, he was one of the incorporators of the pioneering Magnetic Telegraph Company, and from 1850 its president. In this company, he was an associate of the inventor, Samuel F. B. Morse, and the chief promoter, Amos Kendall, another former newspaperman.
Swain was buried in The Woodlands Cemetery.
Swain's son William J. Swain founded a newspaper titled the Public Record in 1870, which later became The Philadelphia Record.