William Mattice (November 15, 1798 – July 27, 1881) was a merchant and political figure in Canada West.
He was born in Cornwall Township in Upper Canada in 1798, the son of United Empire Loyalists.
Mattice was a merchant and also acted as agent for the Bank of Montreal at Cornwall.
His son, William D. Mattice, also represented Stormont in the Legislative Assembly.
His grandson, Gregor Lenox Mattice was honored in the naming of Mattice-Val Côté, Ontario.