The only professional orchestral ensemble in Ireland playing historically authentic instruments, the Irish Baroque Orchestra is among the leading period instrument groups in the British Isles. The players perform only on actual Baroque instruments or modern replicas of these.

The Irish Baroque Orchestra was formed in 1996 by Mark Duley and Thérèse Timoney; Duley was the chorus master of the RTÉ Choir of Ireland's national radio network, and had worked with John Butt and other conductors interested in early music. The Irish Baroque Orchestra cultivates repertory of the 17th and 18th centuries, by no means all of it connected to Ireland, although the group's annual performances of Handel's Messiah, HWV 56, are calendar highlights. Under artistic director Peter Whelan, the group presents an annual concert series and special events at the National Concert Hall in Dublin, as well as touring throughout Ireland. The orchestra has held a residency at the Ardee Baroque Festival in Ireland's County Louth. It enjoys funding from the Dublin City Council and the Arts Council of Ireland. The Irish Baroque Orchestra maintains a training arm, the Irish Youth Baroque Orchestra. The group made its debut in 2010 on the Avie label with Flights of Fancy, an album of early Italian Baroque music that won plaudits from The New Yorker magazine, among others. The group also issued The Irish Baroque Orchestra Plays Bach on the recording label of the RTÉ Lyric FM radio network. The Irish Baroque Orchestra then signed with Scotland's Linn label and released Concerti Bizarri, featuring Baroque violinist Monica Huggett, in 2016. They followed that up with Welcome Home, Mr. Dubourg, an album featuring extant excerpts from the rare Ode for Dublin Castle (1739) by Irish Baroque composer Matthew Dubourg as well as Italian works, in 2019. In the fall of 2019 the group backed an Irish National Opera cast in performances of Vivaldi's opera Griselda. ~ James Manheim, Rovi