The origins of University College Dublin date back to its foundation in 1851 as the Catholic University of Ireland. In 1854, the University was established at no. 86 St. Stephen's Green with John Henry Newman as its first Rector. This Building, and no. 85, which became part of the University in 1865, are now collectively known as Newman House. The building still belongs to UCD and is used for various university functions. Some of the more celebrated literary figures associated with the early days of the University are Gerard Manley Hopkins, James Joyce and Austin Clarke.

The constitution of UCD dates from 1908 when it received its charter and was incorporated as a constituent college of the National University of Ireland. This coincided with the move of UCD, to larger premises in Earlsfort Terrace, Dublin. Earlsfort Terrace still accommodates the Medical Faculty, and part of the Engineering Faculty but the Great Hall, once used for all the significant occasions of the University, has now become the National Concert Hall.

In 1934, University College Dublin bought Belfield House and during the years 1949 to 1958 purchased a group of adjoining properties. In 1960, the Government recommended that UCD should move from the city centre to Belfield. The first buildings to be completed on the campus were those of the Faculty of Science in 1964. The other faculties moved to Belfield on a phased basis as their new buildings were completed.

The main campus of UCD is situated on the 132 hectare site at Belfield, 5km south of the centre of Dublin city. This campus is an attractively landscaped complex of modern architectural buildings, accommodating most of the Faculties of the University as well as its student residences and numerous leisure and sporting facilities. The School of Physiotherapy is situated in the Mater Misericordiae University Hospital while UCD's School of Diagnostic Imaging is located in Herbert Avenue, close to St Vincent's University Hospital. The Michael Smurfit Graduate School of Business is located on the campus at Blackrock, and in Lyons Estate, Kildare, the Faculty of Agriculture runs a research farm.

University College Dublin is currently engaged in an expansive phase of physical development on the Belfield campus. The new Veterinary School and Teaching Hospital completed in July 2002, provides its students with a state of the art facility. The new Veterinary School replaces the Veterinary College which was established in Ballsbridge in 1900. The Quinn School of Business for undergraduate Commerce students, which opened in September 2002, is the first university building in Europe designed with a special focus on e-technology and e-learning. The construction of the building for the Conway Institute for Biomedical and Biomolecular Research is nearing completion. It will facilitate the work of the researchers at this Institute, in the identification of novel therapeutic treatments for human and animal diseases. The third student village, Glenomena opened in September 2002 with accommodation for 270 students. When completed in September 2003, Glenomena will accommodate 550 students in total. Site works have also begun on Phase 1 of the Health Sciences Complex, which will enable the Schools of Diagnostic Imaging, Physiotherapy and Nursing and Midwifery to locate onto the Belfield campus. UCD recently purchased the Philips site and buildings adjacent to the Belfield campus at Clonskeagh. This property is considered suitable for the relocation of the Departments of Civil and Agricultural & Food Engineering from Earlsfort Terrace, which will bring some of the remaining off campus elements of the university to Belfield.

With ten faculties and over eighty departments, UCD is now the largest single university institution in Ireland, offering a comprehensive range of undergraduate and postgraduate programmes in the humanities and sciences. Its student population is approximately 22,000, including 2,000 international students. Approximately 25% of the student body are engaged in postgraduate study and research. UCD has a strong research base which is reflected in the value of research contracts signed in 2001/02, the figure rose to EUR41.75m, EUR33.86m the previous year. The University is committed to maintaining this high level of research activity and to further developing its collaborative links with industry and commerce, and with educational and research institutions internationally.