Zombie apocalypse is a subgenre of apocalyptic and post-apocalyptic fiction in which society collapses due to overwhelming swarms of zombies. Typically only a few individuals or small bands of survivors are left living. In some versions, the reason the dead rise and attack humans is unknown, in others, a parasite or infection is the cause, framing events much like a plague. Some stories have every corpse rise, regardless of the cause of death, whereas others require exposure to the infection.

Apocalyptic and post-apocalyptic fiction is a subgenre of science fiction in which the Earth's civilization is collapsing or has collapsed. The apocalypse event may be climatic, such as runaway climate change; astronomical, such as an impact event; destructive, such as nuclear holocaust or resource depletion; medical, such as a pandemic, whether natural or human-caused; end time, such as the Last Judgment, Second Coming or Ragnarök; or any other scenario in which the outcome is apocalyptic, such as a zombie apocalypse, cybernetic revolt, technological singularity, dysgenics or alien invasion.