Day Zero

Day Zero may refer to:


 * Day Zero (2007 film), an American drama
 * Day Zero (2020 film), an Iranian action thriller
 * Day Zero (2022 film), a Philippine action zombie film
 * Day Zero: The Series, a 2011–2014 American post-apocalyptic drama television series
 * Day Zero (novel), a 2021 science fiction novel by C. Robert Cargill
 * "Day Zero", 19 June 2019, during the 2019 Chennai Water Crisis, when all four reservoirs supplying the city ran dry
 * "Day Zero", during the 2010s Cape Town water crisis, a reference to the day water restrictions would be implemented