Michael William Gallagher (born 29 October 1945) is an English Hammond organ, piano and synthesiser player best known as a member of Ian Dury and the Blockheads and for his contributions to albums by the Clash. He has also written music for films such as Extremes (1971) and After Midnight (1990), and the Broadway play Serious Money (1987).

Mick Gallagher started his musical career in Newcastle with The Unknowns in the early 1960s. He played with the Animals during 1965, replacing their founding member Alan Price. He moved on to form The Chosen Few, where he played alongside Alan Hull, who later formed Lindisfarne. Other associations include Skip Bifferty, Peter Frampton's Camel and Cochise.

In 1977 Gallagher was playing in a band called Loving Awareness, including John Turnbull, Charley Charles and Norman Watt-Roy. Charles and Watt-Roy worked as session musicians with Ian Dury, and when the group went on tour, Gallagher and Turnbull were invited along. This band became the Blockheads.

Under the management of Andrew King and Peter Jenner, the original managers of Pink Floyd, Ian Dury and the Blockheads quickly gained a reputation as one of the top live acts of new wave music. The Blockheads' sound drew from its members' diverse musical influences, which included jazz, rock and roll, funk, reggae and Dury's love of music hall. Gallagher's Hammond sound was a major contribution to the band.

The single "Sex & Drugs & Rock & Roll", released 26 August 1977, marked Blockheads' Stiff debut. Although it was banned by the BBC, it was named Single of the Week by NME on its release. The single issue was soon followed at the end of September by the album New Boots and Panties!!, which, although it did not include the single, achieved platinum status.

In October 1977 Gallagher and the band started performing as Ian Dury & the Blockheads, when the band signed on for the Stiff "Live Stiffs Tour" alongside Elvis Costello & the Attractions, Nick Lowe, Wreckless Eric and Larry Wallis. The tour was a success, and Stiff launched a concerted Ian Dury marketing campaign, resulting in the Top Ten hit "What a Waste", and the hit single "Hit Me with Your Rhythm Stick", which reached No. 1 in the UK at the beginning of 1979, selling just short of a million copies. Again, "Hit Me" was not included on the original release of the subsequent album Do It Yourself. Both the single and its accompanying music video featured Davey Payne playing two saxophones simultaneously during his solo, in evident homage to jazz saxophonist Rahsaan Roland Kirk, whose "trademark" technique this was. With their hit singles, the band built up a dedicated following in the UK and other countries, and their next single "Reasons to be Cheerful, Part 3" made number three in the UK.

The band's second album, Do It Yourself, was released in June 1979 in a Barney Bubbles-designed sleeve of which there were over a dozen variations, all based on samples from the Crown wallpaper catalogue. Bubbles also designed the Blockhead logo.

Chas Jankel left the band temporarily and relocated to the U.S. after the release of "What a Waste" (his organ part on that single was overdubbed later) but he subsequently returned to the UK and began touring sporadically with the Blockheads, eventually returning to the group full-time for the recording of "Hit Me with Your Rhythm Stick"; according to Gallagher, the band recorded 28 takes of the song, but eventually settled on the second take for the single release. Partly due to personality clashes with Dury, Jankel left the group again in 1980 after the recording of the Do It Yourself LP, and he returned to the US to concentrate on his solo career.