Irish dance refers to the traditional dance forms that originate in Ireland, including both solo and group dance forms, for social, competitive, and performance purposes. Irish dance has evolved over centuries and is believed to have its roots in ancient Celtic dance. In the 17th and 18th centuries, dance was taught by "travelling dance masters" across Ireland, and separate dance forms developed according to regional practice and differing purposes. Irish dance became a significant part of Irish culture, particularly for Irish nationalist movements. From the early 20th century, a number of organisations promoted and codified the various forms of dance, creating competitive structures and standardised styles. Irish dancers who compete for competitive reasons dance in a dance style that is more modern than traditional Irish dance. It is mainly done solo, but there is some team dancing in groups of 2, 3, 4, 6, 8, 10, 16 or more.
Solo Irish dance includes the most well-known form of Irish dance, Irish stepdance, which was popularized from 1994 onwards by shows such as Riverdance, and which is practised competitively across not only the Irish diaspora but by many people of disparate cultural backgrounds. Stepdance is characterised by the rigid upper body and intricate footwork of its performers. Other forms of solo Irish dance include sean-nós dance, a relaxed and social dance style involving improvised steps, and festival Irish dance, a style which separated from step dance in the mid-20th century.