A horse race run twice a year in the Italian city of Siena. The race is run in July and in August between 10 of the 17 Contrade of the city and takes place in the central Piazza del Campo.

The prize is the Palio, a long banner typically depicting the Madonna bestowing her heavenly blessing upon the city and the contrade. A new banner is created for each competition, usually by an important Italian artist. Not surprisingly there are frequently disputes about the artistic merits of the banners: the Palio of August 1999, for example, attracted criticism from traditionalists for being too modern in style: but it was none the less prized by the contrada (Chiocciola) that won it!

The race has been run in more or less its present form since at least the 19th Century, but its origins are even older. It is justly famous for the fierceness of the rivalry between the competitors, and death and serious injury is not uncommon among both riders ('fantini') and horses, although steps continue to be taken to improve the safety of the race. Like the Grand National in England, the race is considered by some to be cruel to the animals involved, although the Sienese would point out that the horses are treated with great, even excessive care before and after the race; and, although the riders are equipped with whips, these are only for use on the other riders (whipping the horse will lead to disqualification).

In 2000 the city proposes to hold an extra 'Palio Straordinario' in September, to commemorate the millennium.