More than 400,000 people are expected in the Co Clare town
President Michael D Higgins will head to County Clare today to officially open the annual Fleadh Cheoil na hÉireann.
The traditional music and arts festival is an important marking on the Irish culture calendar - as well as a major competition for traditional musicians and performers.
More than 400,000 people are expected to arrive in Ennis over the next week.
It is the third time the festival has taken place in the town, and the first time since 1977.
This year's Fleadh runs until August 22nd.
Alongside the concerts and competitions, other events at the festival will include culture tours and the Scoil Éigse summer school.
The full details of this year's festivities are available on the Fleadh website.
Chairman of the executive committee Micheál O'Riabhaigh says the event remains hugely popular.
He highlights that around 20% of the visitors to Fleadh Cheoil come from abroad.