Jack Hamilton Warren, OC (April 10, 1921 – April 1, 2008) was the Canadian High Commissioner to the United Kingdom from 1971 to 1974 then Canadian Ambassador to the United States from 1975 to 1977. A World War II Royal Canadian Navy veteran, he was Vice-Chairman and a Director of the Bank of Montreal from 1979 to 1986. From 1986 to 1990, he was the Deputy North America Chairman of the Trilateral Commission.In 1982, he was made an Officer of the Order of Canada.