The Dublin Marathon is an annual marathon in Dublin, Ireland, normally held on the last Monday in October, which is a public holiday in Ireland. Held each year since 1980, the marathon now attracts over 15,000 participants.

The course is generally reasonably flat. It starts at Fitzwilliam Square in the city center and concludes at Merrion Square. Exact routing varies, although in recent years the race has proceeded in an anti-clockwise direction around the city, including passing through the Phoenix Park. The marathon course is a single lap, starting and finishing close to the City Centre. The Irish climate is influenced by the prevailing light south-westerly winds of the Gulf Stream. The average temperatures of October are around 14-14°C (53-57°F). Dublin has only about 30 inches of rain annually, making it ideal for running.