Celtic art is art associated with various peoples known as Celts speaking the Celtic languages in Europe from pre-history through to the medieval period and beyond, as well as art of ancient peoples whose language is unknown but where cultural and stylistic similarities lead archaeologists to consider it probable that they were predecessors of those known to speak Celtic languages, and Celtic revival art from the 18th century to the modern era which began as a conscious effort by Modern Celts to express self-identification and nationalism.

Celtic art is ornamental, avoiding straight lines and only occasionally using symmetry, without the imitation of nature or ideal of beauty central to the classical tradition, but as far as we can understand it often involves complex symbolism. It includes a variety of styles and often incorporates subtly modified elements from other cultures, an example being the characteristic over-and-under interlacing which only arrived in the 6th century when it was already in use by Germanic artists.

There are three "traditions" of Celtic art, the first being the continental Iron age art mainly associated with La Tène culture which draws on native, classical and (perhaps via the Mediterranean) oriental sources. The second, Iron age art in Britain and Ireland, draws on the continental tradition while adding distinctive regional styles. The third, the Celtic "renaissance" of the early Middle Ages in Ireland and to a lesser extent in parts of Britain, borrows heavily from Roman motifs. This third tradition formed the basis for the relatively recent Celtic revival art.