- Mal SpoonerBorn in: LeekDecade started: 1940s
- Malcolm McLarenFormed / started: 22 January 1946Split up / ended: 8 April 2010
- Malcolm MorleyDecade started: 1960sGenres: rock music
- Malcolm TomlinsonBorn in: IsleworthDecade started: 1960s
- Manfred MannBorn in: JohannesburgDecade started: 1960s
- Marc AlmondFormed / started: 9 July 1957Note: English pop singer and songwriter
- Marc BolanFormed / started: 30 September 1947Split up / ended: 16 September 1977
- Marc EllingtonFormed / started: 16 December 1945Split up / ended: 17 February 2021
- Marianne FaithfullFormed / started: 29 December 1946Split up / ended: 30 January 2025
- Mark E. SmithFormed / started: 5 March 1957Split up / ended: 24 January 2018
- Mark FrithDecade started: 2000sGenres: rock music
- Mark NorthfieldDecade started: 1990sGenres: rock music
- Mark ParryDecade started: 2000sGenres: rock and roll
- Mark RonsonFormed / started: 4 September 1975Note: British DJ and producer
- Mark ShawBorn in: ChesterfieldDecade started: 1980s
- Mark StewartFormed / started: 10 August 1960Split up / ended: 21 April 2023
- Martin ArmigerBorn in: HitchinDecade started: 1970s
- Martin BelmontBorn in: BromleyDecade started: 1940s
- Martin BirchFormed / started: 27 December 1948Split up / ended: 9 August 2020
- Martin BrammerBorn in: SeahamDecade started: 1950s
- Martin CiliaBorn in: RochfordDecade started: 1970s
- Martin WalkyierDecade started: 1980sGenres: heavy metal music
- Marty WildeBorn in: BlackheathDecade started: 1950s
- Marty Willson-PiperBorn in: StockportDecade started: 1980s
- Matt HydeDecade started: 2000sGenres: heavy metal music
- Matt MonroFormed / started: 1 December 1930Split up / ended: 7 February 1985
- Matthew StrachanBorn in: BalhamDecade started: 1980s
- Matthew TuckBorn in: BridgendDecade started: 1990s
- Maurice CoyneBorn in: City of LondonDecade started: 1970s
- Maurice GibbFormed / started: 22 December 1949Split up / ended: 12 January 2003
- Max MilnerDecade started: 1990sGenres: rock music
- Maxi PriestFormed / started: 10 June 1961Note: British reggae vocalist of Jamaican descent
- Mehrdad BadieBorn in: BakuDecade started: 1950s
- Mel PritchardBorn in: OldhamDecade started: 2000s
- Michael BallFormed / started: 27 June 1962Note: British actor, singer, and radio and TV presenter
- Michael HayesFormed / started: 20 June 1938Split up / ended: 30 May 2003
- Michael PagetBorn in: BridgendDecade started: 1990s
- Michael ThomasBorn in: BridgendDecade started: 1990s
- Mick AbrahamsFormed / started: 7 April 1943Split up / ended: 19 December 2025
- Mick BarnardBorn in: United KingdomDecade started: 1950s
- Mick FarrenFormed / started: 3 September 1943Split up / ended: 27 July 2013
- Mick GlossopBorn in: MerseysideDecade started: 1970s
- Mick KarnFormed / started: 24 July 1958Split up / ended: 4 January 2011
- Mick RalphsFormed / started: 31 March 1944Split up / ended: 23 June 2025
- Mick RonsonFormed / started: 26 May 1946Split up / ended: 29 April 1993
- Mick StevensFormed / started: 1953Split up / ended: 1987
- Mick UnderwoodFormed / started: 5 September 1945Split up / ended: 28 July 2024
- Mick UnderwoodBorn in: MiddlesexDecade started: 1960s
- Mick WeaverBorn in: BoltonDecade started: 1940s
- Mickey DaleBorn in: Worth ValleyDecade started: 1960s
- Mickey GeeBorn in: CardiffDecade started: 2000s
- Mickey JuppBorn in: WorthingDecade started: 1960s
- MIKAFormed / started: 18 August 1983Note: Lebanese-born English pop singer
- Mike BerryFormed / started: 24 September 1942Split up / ended: 11 April 2025
- Mike CooperFormed / started: 24 August 1942Note: UK folk blues vocalist and guitarist
- Mike DawesFormed / started: 21 July 1989Note: English fingerstyle guitar player, arranger, composer
- Mike d’AboFormed / started: 1 March 1944Note: English singer‐songwriter, former frontman of Manfred Mann
- Mike GroseBorn in: United KingdomDecade started: 1970s
- Mike HarrisonFormed / started: 30 September 1945Split up / ended: 25 March 2018
- Mike HeatonDecade started: 1960sGenres: rock music
- Mike LeanderBorn in: WalthamstowDecade started: 1960s
- Mike OldfieldFormed / started: 15 May 1953Note: English musician, songwriter and producer
- Mike PenderBorn in: KirkdaleDecade started: 1950s
- Mike PetersFormed / started: 25 February 1959Split up / ended: 29 April 2025
- Mike RatledgeFormed / started: 6 May 1943Split up / ended: 5 February 2025
- Mitch MitchellFormed / started: 9 July 1946Split up / ended: 12 November 2008
- MorrisseyFormed / started: 22 May 1959Note: English singer‐songwriter