Fontainebleau (; French pronunciation: [fɔ̃tɛnblo] (listen)) is a commune in the metropolitan area of Paris, France. It is located 55.5 kilometres (34.5 mi) south-southeast of the centre of Paris. Fontainebleau is a sub-prefecture of the Seine-et-Marne department, and it is the seat of the arrondissement of Fontainebleau. The commune has the largest land area in the Île-de-France region; it is the only one to cover a larger area than Paris itself. The commune is closest to Seine-et-Marne Prefecture, Melun.

Fontainebleau, together with the neighbouring commune of Avon and three other smaller communes, form an urban area of 36,724 inhabitants (2018). This urban area is a satellite of Paris.

Fontainebleau is renowned for the large and scenic forest of Fontainebleau, a favourite weekend getaway for Parisians, as well as for the historic Château de Fontainebleau, which once belonged to the kings of France. It is also the home of INSEAD, one of the world's most elite business schools.

Inhabitants of Fontainebleau are sometimes called Bellifontains.