Eleazer Williams (May 1788 – August 28, 1858) was a Canadian clergyman and missionary of Mohawk descent.
Williams was born in Sault St. Louis, Quebec, Canada, the son of Thomas Williams, and was educated at Dartmouth College. He published tracts and a spelling book in the Iroquois language, translated the Book of Common Prayer into Iroquois, and wrote a biography of Chief Te-ho-ra-gwa-ne-gen (Thomas Williams).
In 1815, Williams joined the Episcopal Church. In 1817, Bishop John Henry Hobart appointed Williams to be a missionary to the Oneida people in upstate New York.
In 1820 and 1821, Williams led delegations of Native Americans to Green Bay, Wisconsin, where they secured a cession of land from the Menominee and Winnebago tribes in the Fox River Valley at Little Chute and along Duck Creek. Historians have disputed the significance of Williams' leadership to this migration compared to that of the Oneida people themselves, including Oneida leader Daniel Bread. The following year Williams made his home there and was married to a Menominee woman named Madeleine Jourdain. In 1826 he was ordained a deacon.
In 1839 and afterwards, Williams began to make the claim that he was the French Lost Dauphin. During the 1850s he openly became a pretender, but he died in poverty at Hogansburg, New York.
Williams was buried at Saint James' Cemetery in Hogansburg on August 28, 1858. In 1947, his remains and tombstone were moved to Holy Apostles Cemetery in Oneida, Wisconsin. His tombstone at Oneida indicates that he was a Freemason.