John Jacob Weinzweig, (March 11, 1913 – August 24, 2006) was a Canadian composer of classical music.
Weinzweig was born in Toronto.
He went to Harbord Collegiate Institute, and studied music at the university.
In 1937, he left for the United States to study under Bernard Rogers.
During the Second World War, he began composing film music, and in 1952 he became a professor at his old university in Toronto.
In the previous year he had co-founded the Canadian League of Composers, and he was actively involved in several other organisations representing musicians and composers.
In 1974, he was made an Officer of the Order of Canada.
In 1988, he was awarded the Order of Ontario.
In 2004, Weinzweig was the recipient of the inaugural Lifetime Achievement Award at the annual SOCAN Awards in Toronto.