Alexander DeWitt (April 2, 1798 – January 13, 1879) was a 19th-century American politician from the state of Massachusetts.
Born in New Braintree, Massachusetts,DeWitt worked in textile manufacturing in Oxford, Massachusetts. He was elected to the Massachusetts state lower house in 1830, serving until 1836. He then served in the State senate in 1842, 1844, 1850, and 1851.
In federal politics, DeWitt was elected as a Free-Soil candidate to the United States Congress in 1853. In January 1854, he was one of six signatories of the "Appeal of the Independent Democrats", drafted to oppose the Kansas-Nebraska Act. He was reelected as a candidate of the American Party to Congress in 1855.
He was defeated in his 1856 bid for reelection and returned to his previous work as a textile manufacturer.
DeWitt died in Oxford on January 13, 1879. He is buried in South Cemetery, one of three in the town.