Glenn Gould was born in Toronto on 25 September 1932 into a musical family: Edvard Grieg was a first cousin of his mother's grandfather, his father was an amateur violinist, and his mother played piano and organ. Gould's mother was his only teacher until he was ten. When he was three years old, it became evident that he possessed exceptional musical aptitude, including absolute pitch and even the ability to read staff notation. At five, he began to compose, and played his own little compositions for family and friends. At the age of six Gould was taken to his first live musical performance which was Josef Hofmann's last appearance in Toronto. It created a lasting and important impression upon the boy. Robert Fulford, a distinguished Canadian author, met Gould when they were both nine and the two families were next-door neighbours. He wrote: "Even as a child Glenn was isolated because he was working like hell to be a great man. He had a tremendous feeling and loving affection for music. . . It was an utter, complete feeling. He knew who he was and where he was going."

At the age of ten, Gould began lessons at the Royal Conservatory of Music in Toronto. Alberto Guerrero was his piano teacher; he studied organ with Frederick C. Silvester and theory with Leo Smith. Gould competed in 1944, at the age of 12, in the annual Kiwanis Music Festival and won the piano trophy. It was to be the only competition Gould would enter, for he later came to be strongly opposed to the idea of young musicians competing with each other and indeed to competition of any sort. In 1945 he passed the associateship examination as a solo performer at the Royal Conservatory, signifying a professional level of attainment. In 1946, at the age of 14, he passed the music theory examinations and was awarded a diploma with highest honors. Gould continued piano lessons with Alberto Guerrero until 1952. Of significant influence upon the teenage Gould were: Artur Schnabel (Gould: "The piano was a means to an end for him, and the end was to approach Beethoven"), Rosalyn Tureck's recordings of Bach ("upright, with a sense of repose and positiveness") and Leopold Stokowski, about whom Gould would later write and produce Stokowski: A Portrait for the Canadian Broadcasting Corporation (CBC).