Britten was born in Lowestoft, Suffolk, the son of a dentist and a talented amateur musician. He showed musical gifts very early in life, and began composing prolifically as a child. He was educated at Old Buckenham Hall School in Suffolk, an all-boys prep school, and Gresham's School, Holt. In 1927, he began private lessons with Frank Bridge; by the following year he had composed Quatre Chansons françaises for soprano and orchestra, though it appears that his abilities as an orchestrator were essentially self-taught rather than learned from Bridge. He also studied, less happily, at the Royal College of Music under John Ireland, with some input from Ralph Vaughan Williams. Although ultimately prevented by his parents (at the suggestion of College staff), Britten had also intended to study with Alban Berg in Vienna. He studied both the piano and the viola; the piano was his only instrument as an adult, but the viola would play a significant role in many of his adult works.[citation needed]

Britten was a prolific juvenile composer; some 800 works and fragments precede his early published works. His first compositions to attract wide attention were the Sinfonietta Op. 1, A Hymn to the Virgin (1930) and a set of choral variations A Boy was Born, written in 1934 for the BBC Singers. In this same period he wrote Friday Afternoons, a collection of 14 songs mostly for unison singing, for the pupils of Clive House School, Prestatyn where Britten's brother, Robert, was headmaster.

In April 1935, he was approached by the film director Alberto Cavalcanti to write the film score for the documentary The King's Stamp, produced by the GPO Film Unit. He subsequently met W. H. Auden, who was also working for the GPO Film Unit; together they worked on the films Coal Face and Night Mail. They also collaborated on the song cycle Our Hunting Fathers Op. 8, radical both in politics and musical treatment, and other works.

Of more lasting importance to Britten was his meeting in 1937 with the tenor Peter Pears, who was to become his musical collaborator and inspiration as well as his life partner. In the same year he composed a Pacifist March (words, Ronald Duncan) for the Peace Pledge Union, of which, as a pacifist, he had become an active member, but the work was not a success and soon withdrawn. One of Britten's most noteworthy works from the 1930s was Variations on a Theme of Frank Bridge for string orchestra, Op. 10, written in 1937.

In early 1939, Britten and Pears followed Auden to America. There, in 1940, Britten composed Seven Sonnets of Michelangelo, the first of many song cycles for Pears. Already friends with the composer Aaron Copland, Britten encountered his latest works Billy the Kid and An Outdoor Overture, both of which manifestly influenced his own music. While in America Britten wrote his first music drama, Paul Bunyan, an operetta (to a libretto by Auden). The period in America was also remarkable for a number of orchestral works, including the Violin Concerto Op. 15, and Sinfonia da Requiem Op. 20 (for full orchestra).

In the meantime, Britten had had his first encounter with Balinese gamelan music through the transcriptions for two pianos made by the Canadian composer Colin McPhee. Britten first met McPhee at Stanton Cottage in the summer of 1939, and the two subsequently performed a number of McPhee's transcriptions for a recording. This musical encounter was to bear fruit decades later in several Balinese-inspired works including The Prince of the Pagodas, Noye's Fludde and Death in Venice.

Britten and Pears returned to England in 1942, and both applied for recognition as conscientious objectors; Britten was initially refused recognition, but gained it on appeal. He completed the choral works Hymn to St. Cecilia (his last large-scale collaboration with Auden) and A Ceremony of Carols during the long sea voyage. He had already begun work on his opera Peter Grimes based on the writings of Suffolk poet George Crabbe, and its première at Sadler's Wells in 1945 was his greatest success thus far. However, Britten encountered opposition from sectors of the English musical establishment and gradually withdrew from the London scene, founding the English Opera Group in 1947 and the Aldeburgh Festival the following year, partly (though by no means solely) to perform his own works. From 1949 to 1951 he had his only private pupil, Arthur Oldham. One of Oldham's achievements was the setting for full orchestra of Britten's Variations on a Theme by Frank Bridge, for the Frederick Ashton ballet Le Rêve de Léonor (1949).

Peter Grimes was the first in a series of English operas, of which Billy Budd (1951) and The Turn of the Screw (1954) were particularly admired. His Shakespeare opera, A Midsummer Night's Dream, followed in 1960. These operas share common themes. Even in his comic opera Albert Herring of 1947, all feature an 'outsider' character excluded or misunderstood by society. Often this is the eponymous protagonist, as in Peter Grimes and Owen Wingrave.

Britten was appointed a Companion of Honour (CH) in the Coronation Honours, 1953.

An increasingly important influence was the music of the East, an interest that was fostered by a tour with Pears in 1957, when Britten was struck by the music of the Balinese gamelan and by Japanese Noh plays. The fruits of this tour include the ballet The Prince of the Pagodas (1957) and the series of semi-operatic "Parables for Church Performance": Curlew River (1964), The Burning Fiery Furnace (1966) and The Prodigal Son (1968). The greatest success of Britten's career was, however, the War Requiem, written for the 1962 consecration of the newly reconstructed Coventry Cathedral.