Simon John Breckenridge Nicol (born 13 October 1950) is an English guitarist, singer, multi-instrumentalist and record producer. He was a founding member of British folk rock group Fairport Convention and is the only founding member still in the band. He has also been involved with the Albion Band and a wide range of musical projects, both as a collaborator, producer and as a solo artist. He has received several awards for his work and career.

Born in Muswell Hill, North London, England, Nicol was the son of a general practitioner, who died in 1964. He began to play guitar at the age of 11 and left school at 15. In 1966 he was asked to join local band the Ethnic Shuffle Orchestra by bass guitarist Ashley Hutchings, and soon left his job at a local cinema to play full-time. They rehearsed above his father's old surgery in Fairport House, which gave its name to the band he and Hutchings formed with Richard Thompson and Shaun Frater as Fairport Convention in 1967.

As Thompson emerged as the lead guitarist, Nicol moved towards rhythm duties and occasional backing vocals. After some line-up changes the band enjoyed a degree of commercial success in their early years, with three albums and appearing on Britain's most popular music programme Top of the Pops in 1969 with the single "Si Tu Dois Partir", which reached number 21 in the UK Charts. Nicol contributed his first composition to the band for their second album What We Did on Our Holidays, the short instrumental "End of a Holiday". Besides contributing rhythm guitar and backing vocals to this album, Nicol also played the autoharp on some songs. He was injured in the accident that killed drummer Martin Lamble on 12 May 1969, but when he and the band recovered they recorded what is usually considered their masterpiece and the most important single album in British folk rock, Liege and Lief (1969), which is credited as the key recording in the creation of the British folk rock genre and which helped institute a major surge of interest in British folk music.

Almost immediately after the release of the album, Hutchings and vocalist Sandy Denny left the band, who were then joined full-time by Dave Swarbrick on fiddle and by bassist Dave Pegg. While Swarbrick, with his knowledge of traditional music, emerged as the leading figure in the band, Nicol had to shoulder a larger share of the vocal duties on the next album Full House (1970). When Thompson left soon after, Nicol also had to take over lead guitar duties. Although never entirely happy with this role, it was generally thought at the time that he acquitted himself well. He also demonstrated that he was a multi-instrumentalist playing bass guitar, viola and dulcimer. He began song writing on the next two albums Angel Delight and "Babbacombe" Lee (both 1971). "Breakfast in Mayfair" on the latter was his first solo song composition with the band, and one of the tracks that made it onto the History of Fairport Convention compilation album (1972). He also took over some of the production duties on Babbacombe Lee, but his efforts were not well received by the band, and this, together with unhappiness with having to fill Thompson's shoes, led him to decide to move on and in 1971 he left the band, the last of the original members to do so.

Just about the time that Nicol left Fairport Convention, Hutchings had also quit Steeleye Span and began to work on the first incarnation of the Albion Country Band to provide backing for his then wife Shirley Collins. Nicol joined the long list of musicians, including former Fairport members Richard Thompson and Dave Mattacks, to contribute to No Roses (1971), often considered one of the most important British folk rock albums. In 1972 Simon Nicol was part of the by now reduced six-piece-line up of the Albion Country Band featuring vocalists Royston Wood and Steve Ashley, Sue Draheim on fiddle, Ashley Hutchings on bass guitar and Dave Mattacks on drums. This band played a session for BBC Radio 1 and contributed one lengthy song to Steve Ashley's debut album.

Along with Dave Mattacks, Ashley Hutchings, singer Royston Wood, singer and multi-instrumentalist Steve Ashley and American fiddler Sue Draheim Nicol then teamed up with Richard Thompson and Linda Peters (later Linda Thompson) to form the trio Hokey Pokey in 1973. In 1974 this trio expanded into the band Sour Grapes that was assembled to tour in support of the Thompsons' I Want to See the Bright Lights Tonight album. Later that year Nicol played on and co-produced the Thompsons' Hokey Pokey album.

In 1973 he played on what is often considered one of the seminal folk/jazz albums of all time, John Martyn's Solid Air. When Hutchings tried to reform the Albion Band for an album in 1973, Nicol joined again, but the resulting work, Battle of the Field, was not released until 1976. Nicol took part in some of sessions for Hutchings' next project the Etchingham Steam Band, but never formally joined the group. Instead, he added electric guitar and occasional drums to Hutchings' and accordionist John Kirkpatrick's project The Compleat Dancing Master which collects excerpts of English literature and both acoustic and electrified traditional dance music. In 1974–1975 he played guitar on Cat Stevens' Numbers (1975) and also formed a band with Chris Spedding, Pat Donaldson and Gerry Conway. However, this 'supergroup' proved abortive before any recordings were made. Nicol also produced the album Rough Diamonds (1975) for the highly regarded Jack the Lad, and began to play with Swarbrick and Pegg in a low key trio, Three Desperate Mortgages, which toured student venues across Britain.

In 1976 Nicol also was the main guitarist on Ashley Hutchings' second Morris dance revival project, Son of Morris On. This album also featured Morris tunes Nicol had already played with the Albion Country Band in 1972.