Guy Douglas Hamilton Warrack (6 February 1900, Edinburgh - 12 February 1986, Englefield Green) was a Scottish composer and conductor.
He was the son of John Warrack of the Leith steamship company, John Warrack & Co.
, founded by Guy's grandfather, also called John.He was educated at Cargilfield Preparatory School, Edinburgh, Winchester College and Magdalen College, Oxford.
At Oxford he studied music under Sir Hugh Allen and Dr Ernest Walker.
During his time as a student, he performed as organist at St Columba's United Reformed Church in Oxford, as well as in Edinburgh at churches such as St George's United Free.From 1925-1935 he taught on the faculty of the Royal College of Music.
From 1935-1946 he was principal conductor of the BBC Scottish Symphony Orchestra and from 1948-1951 he was conductor for the Sadler's Wells Theatre Ballet.
He was the father of English music critic John Warrack.