A croissant (French pronunciation: [kʁwasɑ̃] ( listen), anglicised variously as /krəˈsɑːnt/, /kwɑːˈsɒn/, etc.) is a buttery flaky pastry named for its distinctive crescent shape. Croissants are made of a leavened variant of puff pastry. The yeast dough is layered with butter, rolled and folded several times in succession, then rolled into a sheet, a technique called laminating.

Crescent-shaped food breads have been made since the Middle Ages, and crescent-shaped cakes (imitating the often-worshiped Moon) possibly since classical times, The croissant in its current form was invented in Vienna after the victory of the Holy League against the Turks in 1683.

Croissants have long been a staple of French bakeries and pâtisseries. In the late 1970s, the development of factory-made, frozen, pre-formed but unbaked dough made them into a fast food which can be freshly baked by unskilled labor. Indeed, the croissanterie was explicitly a French response to American-style fast food, and today 30–40% of the croissants sold in French bakeries and patisseries are frozen.

This innovation, along with the croissant's versatility and distinctive shape, has made it the best-known type of French pastry in much of the world. Today, the croissant remains popular in a continental breakfast.