Oasis are an English rock band formed in Manchester in 1991. The group initially consists of Liam Gallagher (lead vocals), Paul Arthurs (guitar), Paul McGuigan (bass guitar) and Tony McCarroll (drums), with Liam asking his older brother Noel Gallagher (lead guitar, vocals) to join as a fifth member a few months later to finalise their formation. Noel became the de facto leader of the group and took over the songwriting duties for the band's first four albums. They are characterised as one of the defining and most globally successful groups of the Britpop genre.. They were also at the forefront of the Cool Britannia scene which was a culture of feeling renewed optimism and pride in the UK in the second half of the 1990's.

Oasis signed to independent record label Creation Records in 1993 and released their record-setting debut album Definitely Maybe (1994), which topped the UK Albums Chart and quickly became the fastest-selling debut album in British history at the time. The following year they recorded (What's the Story) Morning Glory? (1995) with new drummer Alan White, in the midst of a highly publicised chart rivalry with peers Blur. Spending ten weeks at number one on the British charts, (What's the Story) Morning Glory? was also an international chart success and became one of the best-selling albums of all time. In addition, it is the fifth-best-selling album in the UK and the biggest-selling album in the UK of the 1990s. The Gallagher brothers featured regularly in tabloid newspapers for their disputes and wild lifestyles. In 1996, Oasis performed two nights at Knebworth for an audience of 125,000 each time, the largest outdoor concerts in UK history at the time. In 1997, Oasis released their third album, Be Here Now. It became the fastest-selling album in UK chart history.

Oasis founding members McGuigan and Arthurs left in 1999 as Oasis released Standing on the Shoulder of Giants (2000). They were replaced by former Heavy Stereo guitarist Gem Archer and former Ride guitarist Andy Bell. White departed in 2004, replaced by Zak Starkey as a guest drummer and a touring member. Oasis released three more studio albums: Heathen Chemistry (2002), Don't Believe the Truth (2005) and Dig Out Your Soul (2008). On 28 August 2009 the group abruptly disbanded in Paris after an argument broke out between Liam and Noel just moments before going on stage for a gig at the Rock en Seine festival. The gig was cancelled and the band split up after Noel left the venue and announced he could not work with Liam anymore.

As of 2024, Oasis have sold over 75 million records worldwide, making them one of the best-selling music artists of all time. They are among the most successful acts in the history of the UK Singles Chart and the UK Albums Chart, with eight UK number-one singles and eight UK number-one albums. The band also achieved three Platinum albums in the US. They won 17 NME Awards, nine Q Awards, four MTV Europe Music Awards and six Brit Awards, including one in 2007 for Outstanding Contribution to Music and one for the "Best Album of the Last 30 Years" for (What's the Story) Morning Glory?. They were also nominated for two Grammy Awards.