Thomas March Clark (1812–1903) was an American Episcopal bishop. He was born at Newburyport, Mass.; graduated at Yale in 1831; studied theology at Princeton, and was licensed to preach as a Presbyterian in 1835. He became an Episcopalian in the following year, and was rector of Grace Church, Boston, for seven years, afterward holding charges in Philadelphia, Hartford, and Providence. In 1854 he was consecrated Bishop of Rhode Island, and in 1899, on the death of Bishop John Williams, of Connecticut, became Presiding Bishop of the Episcopal church in America. His Reminiscences appeared in 1895; among his other works are Early Discipline and Culture (1852), and Primary Truths of Religion (1869). He died at age 91.