Teutates (spelled variously Toutatis, Totatis, Totates) is a Celtic god attested in literary and epigraphic sources. His name, derived from a proto-Celtic word meaning "tribe", suggests he was a tribal deity.
The Roman poet Lucan's epic Pharsalia mentions Teutates, Esus, and Taranis as gods to whom the Gauls sacrificed humans. This rare mention of Celtic gods under their native names in a Latin text has been the subject of much comment. Almost as often commented on are the scholia to Lucan's poem (early medieval, but relying on earlier sources) which tell us the nature of these sacrifices: in particular, that victims of Teutates were immersed headfirst into a small barrel and drowned. This sacrifice has been compared with a poorly understood ritual depicted on the Gundestrup cauldron, some motifs in Irish mythology, and the death of the bog body known as the Lindow Man.
Teutates appears in a number of inscriptions, most of which have been found in border or frontier areas. When these inscriptions pair Teutates with a Roman god, they pair him with Mars. Alongside the inscriptions to Teutates, there are inscriptions to a number of etymologically related deities (Teutanus, Toutanicus, Toutiorix). The presence of these similar deity-names have been used to argue that "Teutates" was a generic name, applied to any tribe's tutelary deity.
Teutates has been linked to Roman rings with TOT inscribed on them, of which over 60 examples are known, found around Lincolnshire in England. These three letters have been repeatedly conjectured to abbreviate "Totatis", a late variant of Teutates's name.