Eau de Cologne (French: [o d(ə) kɔlɔɲ]; German: Kölnisch Wasser [ˈkœlnɪʃ ˈvasɐ]; meaning "Water from Cologne"), or simply cologne, is a perfume originating from Cologne, Germany. Originally mixed by Johann Maria Farina (Giovanni Maria Farina) in 1709, it has since come to be a generic term for scented formulations in typical concentration of 2–5% and also more depending upon its type of essential oils or a blend of extracts, alcohol, and water. In a base of dilute ethanol (70–90%), eau de cologne contains a mixture of citrus oils, including oils of lemon, orange, tangerine, clementine, bergamot, lime, grapefruit, blood orange, bitter orange, and neroli. It can also contain oils of lavender, rosemary, thyme, oregano, petitgrain (orange leaf), jasmine, olive, oleaster, and tobacco.

In contemporary American English usage, the term "cologne" has become a generic term for perfumes marketed toward men. It also may signify a less concentrated, more affordable, version of a popular perfume.