William Ellery ( born December 22, 1727 Newport, Rhode Iceland, colony of the Kingdom of Great Britain; † February 5, 1820 in Newport, Rhode Iceland, USA) as a representative of Rhode Iceland signer of the Declaration of Independence of the United States, making it one of the founding fathers of the United States.
He graduated at the age of 20 years at Harvard College and worked as a merchant, customs clerk and employee of Rhode Iceland General Assembly. Ellery opened in 1770 a law practice. He was active in Rhode Island Sons of Liberty, in 1776 replaced the late Samuel Ward in the Continental Congress and served in the Marine Committee and the Committee on Foreign Relations. He became a judge of the Supreme Court of Rhode Iceland. In 1785 he became an abolitionist. He was the first customs cashier at the port of Newport to the entry into force of the Constitution, and remained so until his death in 1820.
Ellerys father was also named William Ellery.