Simulation Theory is the eighth studio album by English rock band Muse. It was released on 9 November 2018 through Warner Bros. Records and Helium-3. Muse co-produced the album with Rich Costey, Mike Elizondo, Shellback, and Timbaland. Following the darker themes of Muse's prior albums, Simulation Theory incorporates lighter influences from science fiction and 1980s pop culture, with extensive use of synthesisers. The contemporary political climate of the United States informed the lyrics.

Rather than working on the album as a whole, Muse focused on recording a single track at a time. Recording began at AIR Studios in London in early 2017 with Elizondo, before embarking on a tour of North America. Production restarted in Los Angeles in late 2017 with Costey, who previously produced Muse's albums Absolution (2003) and Black Holes and Revelations (2006).

The album cover, designed by Stranger Things artist Kyle Lambert, and its music videos homage 1980s pop culture such as Back to the Future, Michael Jackson's Thriller, and Teen Wolf. Simulation Theory was preceded by the release of singles "Dig Down", "Thought Contagion", "Something Human", "The Dark Side", and "Pressure", along with a 2018 festival tour of North America. It was released in a standard edition alongside two deluxe editions featuring alternate versions of its tracks. A world tour of North America, Europe and South America took place in 2019 to support the album. The album received generally mixed reviews, but became the band's sixth consecutive album to top the UK Albums Chart. A film based on the album and tour, Muse – Simulation Theory, was released in August 2020. As of November 2022, Simulation Theory has sold over one million copies worldwide.