The Right Honourable Sir Richard John Cartwright (December 4 1835 - September 24 1912) was a Canadian businessman and politician. Born and raised in Kingston, Ontario to a United Empire Loyalist family. He was a major landowner in the area and became prominent in Kingston's financial community as president of the Commerical Bank of Canada. He suffered a major blow when his bank failed in 1867.

Cartwright entered politics as a Conservative when he was elected to the Province of Canada's legislative assembly in 1863 as a supporter of John A. Macdonald. In 1867 was elected to the newly formed Canadian House of Commons upon confederation, again as a Tory. In 1869, he broke with the Conservatives over Macdonald's appointment of Sir Francis Hincks as Minister of Finance and crossed the floor to joined the Liberal Party of Canada.

With the Liberal party's victory in 1873, Cartwright was appointed Minister of Finance by Prime Minister Alexander Mackenzie. He supported free trade but supported limited tariffs as a means of government revenue. Cartwright returned to the opposition bench when the Liberals were defeated in the 1878 Canadian election. As a recognition of his service he was awarded a knighthood in 1879. In the 1890s the Liberals moved away from support for unrestricted reciprocity with the United States and Cartwright's influence in the party diminished.

With the victory of Wilfrid Laurier's Liberals in the 1896 Canadian election, Cartwright returned to Cabinet but was denied the finance ministry as a means of assuring Canada's business community that the government was not going to adopt free trade. Instead, he was appointed Minister of Trade and Commerce. He also served as a Canadian member of the Anglo American Joint High Commision to resolve diplomatic problems between Canada and the US in 1898. Cartwright was appointed to the Imperial Privy Council in 1902 (allowing him to use the honorific Right Honourable).

In 1904 he was elevated to the Canadian Senate but remained Trade and Commerce minister until the fall of the Laurier government in the 1911 Canadian election, in this position he introduced, in 1908,. a limited system of old age annuities. Additionally, he served as Leader of the Government in the Senate from 1909 until 1911 and as Leader of the Opposition in the Senate from 1911 until his death in 1912.