Cernunnos ("the Horned One," from Gaulish *karnon, "horn") was the antlered god of the Gaulish pantheon, depicted with the antlers of a stag, often seated cross-legged in a meditative posture, surrounded by animals (a stag at one side, a great horned serpent at the other, sometimes a dog or wolf, sometimes a bull). He was a god of the wild, of animals, of fertility, of the nether-world. The most famous depiction is on the silver Gundestrup Cauldron (c. 100 BCE, found in a Danish bog in 1891 and now in the Copenhagen National Museum, the masterpiece of pre-Roman Celtic art), where the antlered figure sits cross-legged amid animals, holding a torc in one hand and a horned serpent in the other. He is named only on a single Roman-era inscription from Paris (the Pillar of the Boatmen, 1st c. CE) and a few other monuments, but his iconographic distinctiveness has made him among the most recognizable Celtic deities.

The figure has had a remarkable modern afterlife, principally through the modern Wiccan and neo-pagan movements, where Cernunnos has been reconstituted as the "Horned God" of a generalized nature-religion, partly on Continental-Celtic evidence and partly on British folk-traditions of horned figures (Herne the Hunter, the Christian-period demonological iconography of horned devils). The historical Cernunnos was a specific Celtic deity with a specific cult; the modern Horned God is a creative reconstruction that draws on him but is not identical with him.