Thomas Clark (Unknown – October 6, 1835) was a businessman and political figure in Upper Canada.
He was born in Scotland and came to Upper Canada in 1791 to seek employment with his cousin, Robert Hamilton.
Besides his partnership with Street, Clark also had an agreement with John Jacob Astor and others for the shipping and sale of flour.
In 1821, he was selected to a commission to establish a new agreement for sharing revenues with Lower Canada.
Clark's former home, Oak Hall, is now the headquarters for the Niagara Parks Commission.