Belfield is a small enclave, not quite a suburb, in Dún Laoghaire–Rathdown, Ireland. It is synonymous with the main campus of University College Dublin.
Belfield is close to Donnybrook, Ballsbridge, Clonskeagh, Goatstown and Stillorgan and takes its name from Belfield House and Demesne, one of eight properties bought to form the main campus of University College Dublin. It is adjacent to the R138 road.