St Stephen's Green is a garden square and public park located in the city centre of Dublin, Ireland. The current landscape of the park was designed by William Sheppard. It was officially re-opened to the public on Tuesday, 27 July 1880 by Lord Ardilaun. The square is adjacent to one of Dublin's main shopping streets, Grafton Street, and to a shopping centre named after it, while on its surrounding streets are the offices of a number of public bodies as well as a stop on one of Dublin's Luas tram lines. It is often informally called Stephen's Green. At 22 acres (8.9 ha), it is the largest of the parks in Dublin's main Georgian garden squares. Others include nearby Merrion Square and Fitzwilliam Square.

A garden square is a type of communal garden in an urban area wholly or substantially surrounded by buildings; commonly, it continues to be applied to public and private parks formed after such a garden becomes accessible to the public at large. The archetypal garden square is surrounded by tall terraced houses and other types of townhouse. Because it is designed for the amenity of surrounding residents, it is subtly distinguished from a town square designed to be a public gathering place: due to its inherent private history, it may have a pattern of dedicated footpaths and tends to have considerably more plants than hard surfaces or large monuments.