The Vesper is a cocktail that was originally made of gin, vodka, and Kina Lillet. Since that form of Lillet is no longer produced, modern bartenders need to modify the recipe to mimic the original taste.

The drink was popularized by author Ian Fleming (1908–1964) in his 1953 novel Casino Royale in which the character James Bond invents the recipe and names the cocktail. Fleming's Bond calls it a "special martini", and though it lacks the vermouth that defined a martini in Fleming's day it is sometimes called a Vesper martini.

Unlike the vodka martini and the mojito, popularized by previous Bond films, the Vesper did not become a familiar cocktail, likely because the Kina Lillet and later the substitute Lillet Blanc, were not widely distributed. Fleming judged it "unpalatable".