Dennis McDermott OOnt (November 3, 1922 – February 13, 2003) was a Canadian trade unionist who served as Canadian Director of the United Auto Workers from 1968 to 1978 and president of the Canadian Labour Congress from 1978 to 1986. Born in Portsmouth, England, McDermott immigrated to Canada in 1948 and settled in Toronto where he worked as an assembler and welder at the Massey-Harris plant. He became a full-time organizer for the United Auto Workers in Canada (UAW) in 1954. He was elected Canadian Director of the UAW in 1968 and became an international vice-president of the union in 1970.