Celtic Thunder is an Irish singing group and stage show known for its eclectic, theatrical style show. The group is backed by the Celtic Thunder Band on their concert tours, and their live shows are known for the use of dramatic set pieces (often invoking symbols of ancient Celtic mythology), visual effects, and highly choreographed staging.

Since the original group's formation in 2007, Celtic Thunder has released twelve albums as well as ten live performances on DVD, three of which were split into two releases.

Celtic Thunder was conceived in the mind of producer Sharon Browne (Celtic Collections) who started the group in 2007. Celtic Thunder debuted in August 2007 at The Helix in Dublin, Ireland.^[1] They are accompanied by the Celtic Concert Orchestra under the direction of Phil Coulter, the musical director of the group.

In December 2008, 2009 and 2011, Billboard magazine named Celtic Thunder Top World Album Artist.^[2] Their first three albums also placed in the top 10 for World Albums.

In March 2009, Celtic Thunder opened the Saint Patrick's Day Parade in New York City.

On 28 November 2010, Celtic Thunder member Paul Byrom announced his resignation from the group to begin a solo career. He left the group when the 2010 concert tour was over.

In 2011, Damian McGinty (the group's youngest member) entered and won the Oxygen reality show The Glee Project. On 21 August 2011, McGinty announced on The Glee Project's Live Viewing Party, that he would be stepping down from Celtic Thunder due to his new role on Glee.^[3]

In 2011 David Munro became the musical director.

During their 2012 tour, Colm Keegan joined the group in May after winning Auditions for a 6th member for the Mythology taping in August and the 2013 tour. After Ryan Kelly was injured in a fall June 3, Keegan was asked to start immediately for the Atlantic City 2 week residency. Ryan recovered in time for the taping and the tour, Colm was asked to do the fall tour because Ryan was originally not going to be able to go on fall tour until October, was decided to keep Colm in the fall lineup.

On 15 October 2012, Celtic Thunder hosted a special performance at The Pentagon.

In December 2012, Celtic Thunder performed an unplugged concert at the Sullivan Hall, New York, in front of an audience of just over 300 people. The concert was in aid of the victims of Hurricane Sandy and resulted in approximately $50,000 being raised.

On 13 January 2014, after three years with Celtic Thunder, Emmet Cahill announced his decision to take a break from Celtic Thunder.

On 12 March 2014, Sharon Browne announced that George Donaldson, one of the five original Celtic Thunder principal singers since the Celtic Thunder auditions in August 2007, died of a heart attack. He was preparing for the Celtic Thunder Australian tour in May. He is survived by his wife Carrie and daughter Sarah.

On 3 April 2014, Emmet Cahill announced that he would once again be joining Celtic Thunder on the Australian tour.

On 5 April 2014, it was unofficially announced that Emmett O'Hanlon would be filling the place of Emmet Cahill after his departure following the Celtic Thunder Cruise II in November 2014.

On 24 November 2014, it was announced that Damian McGinty would be rejoining Celtic Thunder as a temporary guest artist for their 2015 Very Best of Celtic Thunder Tour.

On 16 December 2015, Colm Keegan announced that he would be taking a break from touring with Celtic Thunder for a year to record a new solo album. Emmet Cahill rejoined Celtic Thunder to replace Keegan.

On 26 April 2016, Keith Harkin announced his departure from the group to focus on his solo career. On that same day, it was announced that Michael O'Dwyer would be replacing him.

Oct 2018 Michael O'Dwyer was unable to do the fall tour do to illness and forced to rest his voice until December. He wasn't given the green light to sing again until the last day of the tour.

2019 Michael O'Dwyer left Celtic Thunder to complete his degree and to work on solo projects.