Lycopene is a naturally occurring carotenoid belonging to the isoprene class of compounds. It was named after being first isolated from tomatoes. Its chemical structure consists of 11 conjugated double bonds and 2 non-conjugated double bonds, and is a non-cyclic planar polyunsaturated hydrocarbon with the molecular formula C₄₀H₅₆.

Lycopene is currently one of the strongest antioxidants discovered in nature. Its rate constant for quenching singlet oxygen is 100 times that of vitamin E and more than twice that of β-carotene.