Nuit Blanche (literally White Night or All Nighter in French) is an annual all-night cultural festival. The festival lasts from sundown until sunrise on the first Saturday and Sunday in October and has, since its premiere in Paris under mayor Bertrand Delanoë in 2002, spread to many other cities internationally, including Brussels, Chicago, Madrid, Montreal, Rome, Tirana, Tel Aviv, São Paulo, Skopje, Toronto, Valletta and Leeds amongst others.

Christophe Girard, Deputy Mayor of Paris, who dreamt up the idea of Nuit Blanche in 2002, travelled to Toronto to help launch the event in 2006. "Toronto certainly loves the magic and the mysteries of the night," said Christophe Girard. "Its people prove they love to be together to share and discover its beauties and secrets in the name of art. Now, Nuit Blanche is part of your history." Attendance at Toronto's inaugural event was estimated by Toronto's City Hall to have been 425,000 people.

Taken off from a similar German festival that began in 1997 (see Long Night of Museums), a Nuit Blanche will typically have museums, private and public art galleries, and other cultural institutions offer free admission to all, with the downtown core of a city itself being turned into a de facto art gallery, providing space for art installations, performances (music, film, dance, performance art), themed social gatherings, and other activities.