Excession is a science fiction novel by Iain M. Banks and the fourth published to feature The Culture. It is a large-scale space opera with a complex plot following many characters across large volumes of space.

The book details the Culture's response to an "Outside Context Problem", the Excession of the title (essentially a Big Dumb Object), is a perfect black-body sphere that appears mysteriously on the edges of Culture space. The Excession is Mysterious and Ineffable for a while, and then disappears. One of the main plot elements is the relationship between the Culture and a civilization appropriately named the Affront, which tends to view all other sentient beings as tools for their amusement. The book, more than any of the other Culture novels, focuses on the Culture's Minds as protagonists.