In Celtic mythology, Taranis is the god of thunder, who was worshipped primarily in Gaul, Hispania, Britain, and Ireland, but also in the Rhineland and Danube regions, amongst others. Taranis, along with Esus and Toutatis, was mentioned by the Roman poet Lucan in his epic poem Pharsalia as a Celtic deity to whom human sacrificial offerings were made. Taranis was associated, as was the Cyclops Brontes ("thunder") in Greek mythology, with the wheel.

Celtic mythology is the body of myths belonging to the Celtic peoples. Like other Iron Age Europeans, Celtic peoples followed a polytheistic religion, having many gods and goddesses. The mythologies of continental Celtic peoples, such as the Gauls and Celtiberians, did not survive their conquest by the Roman Empire, the loss of their Celtic languages and their subsequent conversion to Christianity. Only remnants are found in Greco-Roman sources and archaeology. Most surviving Celtic mythology belongs to the Insular Celtic peoples. They preserved some of their myths in oral lore, which were eventually written down by Christian scribes in the Middle Ages. Irish mythology has the largest written body of myths, followed by Welsh mythology.