O'Donnell + Tuomey is an architectural practice based in Dublin, Ireland described by Architecture Today as one of "the godfathers of contemporary Irish architecture"

The practice was established in 1988 by Sheila O'Donnell and John Tuomey, who had both previously worked for Stirling Wilford in London. The pair formed part of Group 91 Architects, the masterplanners for the regeneration of Dublin's Temple Bar district in the early 1990s. Both directors teach at University College Dublin and have lectured at schools of architecture in Europe, the UK and USA, including Harvard Graduate School of Design, Princeton University, Cambridge University and the AA Architectural Association School of Architecture. In 2010 they were elected Honorary Fellows of the American Institute of Architects. In 2013 the practice received the ICON Architecture Practice of the Year Award.