The Gallery complex consists of four interconnected buildings, namely, Dargan, Milltown, Beit and Millennium Wings:
Dargan Wing Designed by Francis Fowke and inaugurated in 1864 this constitutes the earliest element in the complex. Its exterior design was determined by the requirement to mirror Francis Clarendon's elegant Natural History Museum of 1856 located directly across Leinster Lawn.
Milltown Wing Based on designs from 1892 by Thomas Newenham Deane, the project, inaugurated in 1903, was delivered by his son Thomas Manly Deane who inherited the practice following his father’s passing in 1899.
Beit Wing Based on designs by Frank du Berry, Senior Architect at the OPW this modern addition provided not only additional galleries but also incorporated a library, lecture theatre and restaurant together with the provision of a conservation studio.
Millennium Wing Opened in January 2002, this wing was designed by the London-based practice, Benson & Forsyth, who were awarded the commission following an international competition. The Portland stone clad facade of this building gives directly onto Clare Street a busy thoroughfare directly opposite Trinity College contrasting with the reserved elegance of the original entrance on Merrion Square.