Hamilton Ward Sr. (July 3, 1829– December 28, 1898) was an American lawyer and politician who served as a judge on the Supreme Court of New York, the attorney general of New York, and a Republican member of the United States House of Representatives.

Beginning in 1858 Ward was regularly selected as a delegate to New York's Republican state conventions, and he attended almost every one until 1890.

He was appointed in 1862 by the governor of New York as commissioner to raise and equip troops for the Civil War.

While a Representative, he was Chairman of the Committee on Revolutionary Claims (Fortieth Congress).

Ward was a delegate to the New York State Constitutional Convention of 1890, and was appointed (and subsequently elected) a justice of the New York Supreme Court and served from 1891 to 1895, and in the Appellate Division from 1895 until his death in 1898.