Merrion Square Park, Georgian square and park in central Dublin, Ireland

Merrion Square Park is a public green space in central Dublin, Ireland. The three-sided enclosure consists of Georgian red-brick houses, while the fourth side opens to the garden area with flower beds and tall trees.

The square was laid out from 1762 to a plan by John Smyth and Jonathan Barker for the estate of Viscount FitzWilliam, and the surrounding houses were largely complete by the early 19th century. The gardens were created through a competition won by Benjamin Simpson in 1792. The park stayed private, open only to key-holding residents, until Archbishop Dermot Ryan transferred ownership to the city in 1974.

The park's official name, Archbishop Ryan Park, honoured Dermot Ryan, the Archbishop of Dublin who gave the land to the city in 1974; in September 2010 the city council voted to rename it Merrion Square Park. The square's name comes from Merrion, a district of Dublin, not from any word for light. The park holds a collection of old Dublin street lamp standards, such as the green cast-iron post with a white lantern globe standing on the lawn.

The park gates open daily from morning to evening and stand within walking distance of the National Gallery. Several city bus lines stop right at the corners of the square.

In the southeast corner of the park stands an information panel beside one of the air-raid shelters built in Dublin during the Second World War. The panel states that 1,100 people could spend the night inside it during air raids.