Singer Phil Mogg, guitarist Mick Bolton, bassist Pete Way, and drummer Andy Parker formed the band in August 1969. Originally taking the name Hocus Pocus, the group changed their name in October 1969 to UFO in honour of the London club where they were spotted by Noel Moore, who signed them to Beacon Records label, which was headed by Antiguan-born Milton Samuel. Their eponymously titled first album debuted in 1970 and was a typical example of early hard rock including a heavy version of the Eddie Cochran's classic "C'mon Everybody". Both UFO 1 and its follow-up UFO 2: Flying, were successful in Japan (especially the single "C'mon Everybody" which became a huge hit there) and Germany (the song "Boogie For George," also from the first album, reached No. 30 in German singles charts as well as "Prince Kajuku" from Flying reached No. 26), but generated poor interest in Britain and America. Consequently, their third effort, Live (later re-issued as UFO Lands In Tokyo), was originally only released in Japan in 1971.
Part of UFO's early work was strongly influenced by space rock (their second album, including a 26-minute title track and a 19-minute-long opus "Star Storm", was subtitled One Hour Space Rock) that was modestly popular at the time, but the band soon realised the style was somewhat limited. In January 1972, Mick Bolton left the group, and UFO set out to find a guitarist who could provide the band with a more standard rock sound.
International success (1973–78)
After brief trial runs with Larry Wallis (February - October 1972) and Bernie Marsden (he toured with UFO in Europe and recorded a pair of demos, "Oh My" and "Sixteen") the band recruited Michael Schenker from Scorpions in June 1973. Schenker was only 18 at the time but was already a well-respected guitarist. On a new label, Chrysalis Records,the revamped UFO recorded a non-LP single in 1973, "Give Her The Gun" and "Sweet Little Thing" with producer Derek Lawrence. In 1974 and with a new producer, Leo Lyons (formerly of Ten Years After), UFO recorded Phenomenon, which highlighted the band's harder-edged guitar sound. Phenomenon contains many fan favorites such as "Doctor Doctor" (later a minor hit single as a live track) and "Rock Bottom" (which was extended live to provide a showcase for Schenker). By the time of the Phenomenon tour, ex-Skid Row guitarist Paul Chapman joined the group, but he left in January 1975 to form Lone Star.
Two later albums, Force It (July 1975) and No Heavy Petting (May 1976) (the last was recorded with a regular keyboardist, Danny Peyronel as well as harmony vocalist and also songwriter), and extensive touring brought UFO increased visibility with American audiences and increased their following in the UK. Song Belladonna from No Heavy Petting was very popular in USSR (and then became popular in Russia) after the cover version of Alexander Barykin.
In July, 1976 the band recruited keyboardist and rhythm guitarist Paul Raymond from Savoy Brown to make 1977's Lights Out. This album was the pinnacle of UFO's studio career containing songs such as "Too Hot To Handle," "Lights Out," and the 7-minute opus "Love To Love." With Lights Out, the band received substantial critical acclaim. With their new-found success, the band went back into the studio to record Obsession in 1978. Later that year, the band went on tour in the USA and recorded a live album, Strangers In The Night, which was released in January 1979. Strangers was a critical and commercial success actually reaching Number 8 in the UK album charts in February 1979.
Schenker's departure (1978)
Along with Michael Schenker's increasing alcohol abuse, tensions had begun to grow between Mogg and Schenker in the late 1970s. Soon after UFO's final US show in Palo Alto, California in October 1978 Schenker left the band. He made a brief return to the Scorpions before going on to form his own Michael Schenker Group.
Post-Schenker years (1979–90)
After Schenker's exit, UFO rehired Paul "Tonka" Chapman on guitar who brought over unused track ideas from Lone Star's drummer Dixie Lee. Shortly after they released their next LP, No Place To Run in January, 1980. Produced by the former Beatles producer, George Martin No Place To Run failed to match up to the success of its predecessors, though it fractionally missed the UK Top 10. Paul Raymond left the band at the end of the No Place To Run tour and was replaced by John Sloman from Uriah Heep for a couple of months and then by former Wild Horses guitarist and keyboardist Neil Carter, who helped fill the void in the songwriting left by Schenker's departure. Carter debuted with UFO on stage at the three-day Reading Festival on 23 August 1980, when the band played as the Saturday night headline act. At the beginning of the following year, UFO released the self-produced The Wild, the Willing and the Innocent, which had a lighter pop rock sound, which was popular at the time. The album achieved mild success in the UK, reaching the UK Top 20, and the single "Lonely Heart" was released.
In February 1982 the band released Mechanix. It contained the popular song "Back Into My Life", which was a minor hit in the USA. However, the album was very successful in the UK, where it reached No.8, the band's highest ever placing. Later that year, founding member Pete Way left the band to form Fastway with Motörhead guitarist "Fast" Eddie Clarkeand then his own band, Waysted. He was replaced by Talas bassist, Billy Sheehan. UFO released Making Contact in 1983, but the album was a critical and commercial failure. Thus, that March, UFO decided to disband. The band played a UK farewell tour with Paul Gray (ex Eddie and the Hot Rods and The Damned bassist). However, there was a hint that this might not be permanent, when UFO released a compilation album featuring songs by UFO (as well as other groups featuring ex-members of UFO) entitled Headstone, thesleeve of which showed a headstone, denoting UFO with their formation date but an incomplete end date.
This proved to be a short hiatus as, two years later, Mogg assembled a new UFO line-up, featuring Paul Gray on bass again, ex- Diamond Head drummer Robbie France and Atomic Tommy M (Tommy Mc Clendon) on guitar with Paul Raymond rejoining shortly after and released Misdemeanor. This was followed by the 1988 EP Ain't Misbehavin, on which France was replaced by ex-Magnum drummer Jim Simpson who then was replaced by Fabio Del Rio. Despite the renewed activity of the band, neither release was financially successful and they officially disbanded again in 1989 after a string of guitarists replacing McClendon: Myke Gray of Jagged Edge in late 1987, in 1988 Rik Sanford and Tony Glidewell, while Pete Way rejoined on bass, and finally in 1989 future Cold Sweat guitarist Erik Gamans.
The reunion(s) (1991–2003)
In 1992, Mogg and Way decided to put a new UFO line-up together with Clive Edwards and Laurence Archer in the band and released High Stakes & Dangerous Men. While only released on a small independent label, High Stakes was enough to generate serious interest in a full-blown reunion. The following year, the classic late-1970s UFO line-up – Mogg, Schenker, Way, Raymond and Parker – reunited, and the resulting album was Walk on Water (1995). This line-up (barring Parker's replacement by AC/DC's Simon Wright on drums) went on a world tour. However, tensions arose again, and Schenker left the band in the middle of the tour. Thereafter, the other members again went their separate ways. However, Schenker returned to the fold in 1998 and the band embarked on another tour, with Parker again replaced by a new drummer. They played at the Astoria, Charing Cross Road, London in 1998.
Phil Mogg and Pete Way continued working together throughout this fluctuating band membership, releasing two albums under the Mogg/Way name in the late 1990s, Edge of the World and Chocolate Box.
In 2000, Schenker rejoined UFO again and the band released the double CD Covenant (with Aynsley Dunbar on drums), which contained a disc of new material and a disc of live classics. In 2002, the band recorded Sharks; shortly after Sharks was released, Schenker left the band yet again and was replaced with Vinnie Moore. and the official announcement was made in July 2003  In 2003, Michael Schenker and Pete Way released The Plot with drummer Jeff Martin.
Vinnie Moore and a return to chart success (2004–present)
In 2004 UFO released their 17th studio album You Are Here with their new permanent guitarist Vinnie Moore and Jason Bonham on drums (intermittently). UFO recorded their live set and released a double-DVD recording titled Showtime (2005) along with a double live CD on SPV in November 2005, mixing a number of re-recorded studio songs. In November 2005, Andy Parker returned to the band to play in the Piorno Rock Festival in Granada, Spain. UFO's eighteenth studio album, titled The Monkey Puzzle, was released in 2006.
Andy Parker returned in early 2007 after recovering from leg surgery. On the 2008 tour, Pete Way was unable to get a work visa to enter the United States, Rob De Luca (ex-Sebastian Bach's band,Of Earth, Spread Eagle) filling in.
UFO released their 19th studio album, The Visitor, in June 2009, and followed with a tour of the UK, but without Pete Way, who was suffering from a medical condition. Bass tracks on The Visitor were also played by Peter Pichl, and Pete Way was not credited as a band member on The Visitor cover, nor was any other bassist. However, the album saw UFO's return to the UK Top 100 album charts for the first time in almost 15 years.
In July 2009, UFO released a six-CD live concert box set, containing recordings of six concerts between 1975 to 1982, as well as previously unreleased live songs.
On their 2011 tour, they were accompanied by Barry Sparks playing bass.
Since December 2010, UFO had been working on a twentieth studio album, which was supposed to be released in June 2011. Titled Seven Deadly, was released on 27 February 2012 to almost universally good reviews and a higher chart position than The Visitor also charting in Germany, Sweden, and the Billboard indie charts.
In 2011, former band members Danny Peyronel, Laurence Archer, and Clive Edwards teamed up with bassist Rocky Newton (ex-McAuley Schenker Group) to form a band entitled X-UFO. In live performances, X-UFO played sets of vintage UFO songs.
- Phil Mogg – vocals (1969–83, 1984–89, 1992–present)
- Andy Parker – drums (1969–83, 1988–89, 1993–95, 2005–present)
- Paul Raymond – keyboards, guitar (1976–80, 1984–86, 1993–99, 2003–present)
- Vinnie Moore – guitar (2003–present)
- Pete Way – bass (1969–82, 1988–89, 1992–2004, 2005–11)
- Mick Bolton – guitar (1969–72)
- Colin Turner – drums (1969)
- Larry Wallis – guitar (1972)
- Bernie Marsden – guitar (1973)
- Michael Schenker – guitar (1973–78, 1993–95, 1997–98, 2000, 2001–03)
- Paul Chapman – guitar (1974–75, 1977, 1978–83)
- Danny Peyronel – keyboards, piano (1975–76)
- John Sloman – keyboards (1980)
- Neil Carter – keyboards, guitar (1980–83)
- Billy Sheehan – bass (1982–83)
- Paul Gray – bass (1983–87)
- Tommy McClendon (aka Atomik Tommy M) – guitar (1984–86)
- Robbie France† – drums (1984–85)
- Jim Simpson – drums (1985–87)
- David Jacobson – keyboards (1986)
- Myke Gray – guitar (1987)
- Rik Sandford – guitar (1988)
- Tony Glidewell – guitar (1988)
- Fabio Del Rio – drums (1988)
- Erik Gamans – guitar (1988–89)
- Laurence Archer – guitar (1992–95)
- Jem Davis – keyboards (1992–93)
- Clive Edwards – drums (1992–93)
- Simon Wright – drums (1995–96, 1997–99)
- Leon Lawson – guitar (1995–96)
- John Norum – guitar (1996)
- George Bellas – guitar (1996)
- Aynsley Dunbar – drums (1997, 2000, 2001–04)
- Matt Guillory – guitar (1997)
- Jeff Kolmann – guitar (1998–99), bass (2005)
- Louis Maldonado – keyboards (2000)
- Jeff Martin – drums (2000)
- Jason Bonham – drums (2004–05)
- Barry Sparks – bass (2004, touring: 2011)