Michael Gordon Oldfield (born 15 May 1953) is an English retired musician, songwriter and producer best known for his debut album Tubular Bells (1973), which became an unexpected critical and commercial success. Though primarily a guitarist, Oldfield played a range of instruments, which included keyboards and percussion, as well as vocals. He had adopted a range of musical styles throughout his career, including progressive rock, world, folk, classical, electronic, ambient and new age music. His discography includes 25 studio albums, nine of which have reached the UK top ten.

Oldfield took up the guitar at age ten and left school in his teens to embark on a music career. From 1967 to 1970, he and his sister Sally Oldfield were a folk duo, the Sallyangie, after which he performed with Kevin Ayers before starting work on Tubular Bells in 1971. The album caught the attention of Richard Branson, who agreed to make it the first ever release on his new label Virgin Records. Its opening was used in the horror film The Exorcist and the album went on to sell over 2.7 million copies in the UK. Oldfield followed it with Hergest Ridge (1974), Ommadawn (1975) and Incantations (1978). Like Tubular Bells, these albums consist of longform, mostly instrumental pieces.

In the late 1970s, Oldfield began to tour and release more commercial and song-based music, beginning with Platinum (1979), QE2 (1980) and Five Miles Out (1982). His most successful album of this period was Crises (1983), which features the worldwide hit single "Moonlight Shadow" with vocalist Maggie Reilly. After leaving Virgin and signing with WEA, the 1990s saw him release Tubular Bells II (1992) and Tubular Bells III (1998) among other albums, and he experimented with virtual reality and gaming content with his MusicVR project. In 2012, Oldfield performed at the opening ceremony for the 2012 Olympic Games held in London, while 2017 saw the release of his final album, Return to Ommadawn. Oldfield's label announced his retirement in 2023.

Michael Gordon Oldfield was born in Reading, Berkshire, on 15 May 1953, to Raymond Henry Oldfield (1923–2016), an English general practitioner, and Maureen (née Liston 1919-1975), an Irish nurse from Charleville, County Cork, who emigrated to England to pursue career in nursing. Oldfield has two elder siblings, sister Sally and brother Terence. In 1959, when Oldfield was six, his mother gave birth to a younger brother, David, who had Down syndrome. The parents dropped off David in an institution and lied to Mike, Sally and Terence that the baby had died in infancy. His mother was prescribed barbiturates, to which she became addicted, and developed mental health problems. She spent much of the rest of her life in mental institutions and died in early 1975, shortly after Oldfield had started writing Ommadawn. Oldfield attended Highlands Junior School, followed by St. Edward's Preparatory School and Presentation College, all in Reading. When he was thirteen, the family moved to Harold Wood, Essex, and Oldfield attended Hornchurch Grammar School where, having already displayed musical talent, he earned one GCE qualification in English.

Oldfield took up the guitar aged ten, first learning on a 6-string acoustic which his father had given to him. He learned technique by copying parts from songs, by folk guitarists Bert Jansch and John Renbourn, that he played on a portable record player. He tried to learn musical notation but was a "very, very slow" learner, saying: "If I have to, I can write things down. But I don't like to." By the time he was twelve, Oldfield played the electric guitar and performed in local folk and youth clubs and dances, earning as much as £4 (equivalent to £98 in 2023) per gig. During a six-month break from music that Oldfield had around this time, he took up painting. In May 1968, when Oldfield turned fifteen, his school headmaster requested that he cut his long hair. Oldfield refused, left abruptly and never returned. It was at this point when he decided to pursue music on a full-time, professional basis.

After leaving school Oldfield accepted an invitation from his sister Sally to form a folk duo the Sallyangie, taking its name from her name and Oldfield's favourite Jansch tune, "Angie". They toured England and Paris and signed a deal with Transatlantic Records, for which they recorded one album, Children of the Sun (1969). After they split in the following year Oldfield had a nervous breakdown. He auditioned as bassist for Family in 1969 following the departure of Ric Grech, but the group did not share Roger Chapman's enthusiasm towards Oldfield's performance. Oldfield spent much of the next year living off his father and performing in an electric rock band named Barefoot that included his brother Terry on flute, until the group disbanded in early 1970.

In February 1970, Oldfield auditioned to become the bassist in the Whole World, a new backing band that former Soft Machine vocalist Kevin Ayers was putting together. He landed the position despite the bass being a new instrument for him, but he also played occasional lead guitar and later looked back on this time as providing valuable training on the bass. Oldfield went on to play on Ayers's albums Shooting at the Moon (1970) and Whatevershebringswesing (1971), and played mandolin on Edgar Broughton Band (1971). All three albums were recorded at Abbey Road Studios, where Oldfield familiarised himself with a variety of instruments, such as orchestral percussion, piano, Mellotron and harpsichord, and started to write and put down musical ideas of his own. While doing so Oldfield took up work as a reserve guitarist in a stage production of Hair at the Shaftesbury Theatre, where he played and gigged with Alex Harvey. After ten performances Oldfield grew bored of the job and was fired after he decided to play his part for "Let the Sunshine In" in 7/8 time.

By mid-1971, Oldfield had assembled a demo tape containing sections of a longform instrumental piece initially titled "Opus One". Attempts to secure a recording deal to record it professionally came to nothing. In September 1971, Oldfield, now a session musician and bassist for the Arthur Louis Band, attended recording sessions at The Manor Studio at Shipton-on-Cherwell, Oxfordshire, owned by businessman Richard Branson and run by engineers Tom Newman and Simon Heyworth. Branson already had several business ventures and was about to launch Virgin Records with Simon Draper. Newman and Heyworth heard some of Oldfield's demos and took them to Branson and Draper, who eventually gave Oldfield one week of recording time at The Manor, after which Oldfield had completed what became "Part One" of his composition, Tubular Bells. He recorded "Part Two" from February to April 1973. Branson agreed to release Tubular Bells as the first record on the Virgin label and secured Oldfield a six-album deal with an additional four albums as optional.