Stephen Lewis, the Canadian politician and diplomat who served as an Ontario MPP from 1963 to 1978, died on March 31, 2026, of cancer.

He was elected to the Legislative Assembly of Ontario in 1963 and led the Ontario New Democratic Party from 1970 to 1978. In 1975, he became leader of the province’s Official Opposition.

Lewis later served as Canadian ambassador to the United Nations from 1984 to 1988 and as the U.N. special envoy for HIV/AIDS in Africa from 2001 to 2006.

Stephen Henry Lewis CC (November 11, 1937 – March 31, 2026) was a Canadian politician, public speaker, broadcaster and diplomat who served as leader of the Ontario New Democratic Party (ONDP) from 1970 to 1978. Elected to the Legislative Assembly of Ontario in 1963 at the age of 26, he became the province’s leader of the Official Opposition in 1975. He later served as the Canadian ambassador to the United Nations from 1984 to 1988.