Martin Patrick O'Connell, PC (August 1, 1916 – August 11, 2003) was a Canadian politician. Born in Victoria, British Columbia, he received a Bachelor of Arts from Queen's University. During World War II, he was a captain in the Royal Canadian Army Service Corps. After the war, he received an MA and a Ph.D from the University of Toronto. After his defeat in the 1972 General Election, O'Connell served as Principal Secretary to Prime Minister Trudeau from 1973 until he was once again elected to the House of Commons in the 1974 General Election.