Isaac Chauncey (20 February 1779 – 27 January 1840) was an officer in the United States Navy.

Chauncey, born in Black Rock, Connecticut , 20 February 1779, was appointed a Lieutenant in the Navy from 17 September 1798. He fought with gallantry in the West Indies during the Quasi-War with France; in the Mediterranean during the War with the Barbary Powers; and commanded John Adams (1804–5), Hornet (1805–6), Washington and the Mediterranean Squadron (1815–1820).

Perhaps his most outstanding service was during the War of 1812 when he commanded the naval forces on Lake Ontario, conducting amphibious operations in cooperation with the Army, and containing the large British squadron stationed there. His last service was as member, and, for 4 years, President, of the Board of Navy Commissioners. Commodore Chauncey died in Washington 27 January 1840.

See USS Chauncey for ships named in his honor.