John Beckwith CM (March 9, 1927 – December 5, 2022) was a Canadian composer, writer, pianist, teacher, and administrator.

Born in Victoria, British Columbia, he studied piano with Alberto Guerrero at the Toronto Conservatory of Music in 1945. Beckwith received a Bachelor of Music (Mus.B.) in 1947 and a Master of Music (Mus.M.) in 1961 from the University of Toronto. In 1950-51, he studied with Nadia Boulanger in Paris. He began teaching at University of Toronto's Faculty of Music in 1952. From 1970 to 1977, he was the dean of the faculty. He was founding director of the Institute for Canadian Music at the University of Toronto. In 1987, he was made a member of the Order of Canada. He retired from the university in 1990.

Beckwith wrote over 160 compositions covering stage, orchestral, chamber, solo and choral genres. He also wrote 17 books, the last of which - Music Annals: Research and Critical Writings by a Canadian Composer - was published shortly before his death in 2022.

In 1945, after several years of studying piano at the Royal Conservatory of Music, Beckwith received a Conservatory scholarship that allowed him to study piano with Alberto Guerrero at the University of Toronto where he obtained his Mus.B. His other teachers included Leo Smith and John Weinzweig. In 1950 he was awarded a second scholarship, this time from the Canadian Amateur Hockey Association. The scholarship allowed him to travel to Paris, where he studied composition under Nadia Boulanger. Under Weinzweig's supervision, Beckwith earned his Mus.M. from the University of Toronto in 1961.

After studying in Paris, Beckwith returned to Toronto to pursue further studies and became active as a performing musician, actor, critic, radio commentator, writer, lecturer and broadcaster. In 1952, he returned to the University of Toronto, but this time as a part-time lecturer at the Faculty of Music. He was appointed full-time lecturer in 1955. He remained in this position for several years, and eventually became dean of the faculty from 1970 to 1977. Beckwith was the first Jean A. Chalmers Professor of Canadian Music and the first director of the Institute for Canadian Music at the University of Toronto. He retired in 1990 to devote more time to composing. Among his notable pupils were Brian Cherney, Gustav Ciamaga, Omar Daniel, John Fodi, Clifford Ford, Ben McPeek, James Rolfe, Clark Ross, Matthew Davidson, and Timothy Sullivan.

While teaching, Beckwith remained active in several areas of the musical community. A co-founder of the Canadian Music Centre in 1959, he wrote for the Toronto Star from 1959 to 1965 as an arts critic and columnist, and was a writer and associate producer of documentaries and music series for CBC Radio. Beginning in 1981, he worked as a director for the Canadian Musical Heritage Society, which he had co-founded that same year. He prepared two of the society's 25-volume series of pre-1950 Canadian-composed music. In 1986, a five-record set of his music was included in the Anthology of Canadian Music series. The Beckwith portrait in the Canadian Composers Portraits series was released in 2003.

A collection of 25 of his music articles and talks was published by Golden Dog Press in 1997 under the title Music Papers. In 2006, his biography In Search of Alberto Guerrero was published by Wilfrid Laurier Press (issued in Spanish translation in 2021). With Brian Cherney, he edited Weinzweig: Essays on His Life and Music in 2011 and, with Robin Elliott, he edited Mapping Canada's Music: Selected Writings of Helmut Kallmann in 2013.

Beckwith's autobiography, Unheard Of: Memoirs of a Canadian Composer, was published by Wilfrid Laurier Press in 2012.