William Robertson (ca 1760 – December 3, 1806) was a businessman and political figure in Upper Canada.
[citation needed] He had close business ties to Robert Hamilton, who had married his brother Samuel's widow, Catherine Askin, in 1785.
After the death of his first wife in 1800, he returned to Great Britain and in 1803 married again, but this marriage lasted only a few months.
In 1795, Robertson was part of a partnership with Ebenezer Allen and Charles Whitney of Vermont, Robert Randall of Philadelphia and several other British subjects in Detroit, including Catherine Askin's father, John Askin, which planned to buy the entire lower Michigan peninsula from the United States government.
His fortune eventually passed to his only great-grandchild Lucy Harris née Ronalds who lived in Eldon House, London, Ontario.