Definitely Maybe is the debut studio album by the English rock band Oasis, released on 29 August 1994 by Creation Records. The album features Noel Gallagher on lead guitar, backing vocals and as chief songwriter, Liam Gallagher on lead vocals, Paul "Bonehead" Arthurs on rhythm guitar, Paul "Guigsy" McGuigan on bass guitar and Tony McCarroll on drums.

The band booked Monnow Valley Studio near Rockfield in late 1993 to record the album; they worked with producer Dave Batchelor, whom Noel Gallagher knew from his time working as a roadie for the Inspiral Carpets. However, sessions were unsatisfactory, and Batchelor was subsequently fired. In January 1994, the group began re-recording the album at Sawmills Studio in Cornwall, where Noel produced sessions alongside Mark Coyle. The results were still deemed unsatisfactory; in desperation, Creation's Marcus Russell contacted engineer and producer Owen Morris, who eventually worked on mixing the album at Johnny Marr's studio in Manchester.

Definitely Maybe was an immediate commercial success in the United Kingdom, having followed on the heels of the singles "Supersonic", "Shakermaker", and the UK top-ten hit "Live Forever", which was also a success on US Rock Airplay. It went straight to number one in the UK Albums Chart and became the fastest-selling debut album in British music history at the time; it went on to be certified 9× platinum by the BPI for sales of over 2.7 million units. It was also successful in the United States, being certified platinum by the Recording Industry Association of America (RIAA). The album went on to sell over 8 million copies worldwide. It is the only Oasis album to feature all five original members completely; drummer Tony McCarroll was ejected from the band in early 1995, but he would still partially appear on their second album on the track "Some Might Say".

Upon release, Definitely Maybe received widespread critical acclaim and helped to spur a revitalisation in British pop/rock music in the 1990s. It was embraced by critics for its optimistic themes and rejection of the negative outlook of much of the grunge music of the time and is regarded as a cornerstone of the Britpop genre, having since appeared in many publications' lists of the greatest albums of all time. In 2006, the NME conducted a readers' poll in which Definitely Maybe was voted the greatest album ever. In 2015, Spin included the album in their list of "The 300 Best Albums of 1985–2014". Rolling Stone ranked the album at number 217 on its 2020 list of the 500 Greatest Albums of All Time.