John Solomon Cartwright, QC (September 17, 1804 – January 15, 1845) was a Canadian businessman, lawyer, judge, farmer and political figure in Kingston, Upper Canada. He was a supporter of the Family Compact, an oligarchic group which had dominated control of the government of Upper Canada through their influence with the British governors. He was also a member of the Compact Tory political group, first in the Legislative Assembly of Upper Canada, and then in the Legislative Assembly of the Province of Canada. Cartwright died of tuberculosis in 1845, aged 40.