Alexander J. Coffin (December 16, 1794 – April 23, 1868 Poughkeepsie, Dutchess County, New York) was an American politician from New York.
He was the son of Eliab Coffin (c. 1756–1841) and Mary (Jenkins) Coffin (b. 1761). On April 8, 1819, he married Lydia Stratton (1798–1832), and they had three children.
He was a presidential elector in 1824.
He was a member of the New York State Senate (8th D.) in 1848 and 1849.
He was buried at the Friends Ground in Poughkeepsie.