Don't Believe the Truth is the sixth studio album by English rock band Oasis. It was released on 30 May 2005 by Big Brother Recordings. It reached number one in the UK Albums Chart with first week sales of 237,865, and is the 32nd fastest selling album ever in the UK. The album entered the US charts at number 12, with 65,000 copies sold in the first week, the highest any Oasis album had reached there since 1997's Be Here Now, although its chart stay was brief. Don't Believe the Truth went triple platinum in the UK in the first week of 2006 (900,000+ sales), and in the US has sold more than 200,000 copies.

As with the previous album, Don't Believe The Truth had significant writing contributions from members other than chief songwriter Noel Gallagher, and the album is the first where all duties were divided between the band members. On some of the tracks regular bass player Andy Bell handled guitar, while Gem Archer and Noel Gallagher contributed bass to other songs. Don't Believe the Truth is the first Oasis record to feature the drumming of Zak Starkey, an auxiliary member of Oasis, who performed and toured with them following the departure of longtime drummer Alan White, and appeared on the DVD praising all members' contributions. The album received positive reviews from critics, and many cited it as Oasis' best album in a decade.

Liam Gallagher also had a larger impact on the album through his developing songwriting. Noel has said that the album is his favourite of Oasis' last four, because all members contributed to it. This, he claims, has given it a different feel from a typically Noel-written Oasis album.

The band embarked on a massive worldwide tour that started off at the London Astoria for their Don't Believe the Truth Tour, visiting 26 countries and playing to 3.2 million people at a total of 113 concerts. This resulted in the making of Lord Don't Slow Me Down, a film later released on DVD. To date, the album has sold seven million copies worldwide.