The Fagaceae (/fəˈɡeɪsi.iː, -ˌaɪ/; from Latin fagus 'beech tree') are a family of flowering plants that includes beeches, chestnuts and oaks, and comprises eight genera with about 927 species.

[2] Fagaceae in temperate regions are mostly deciduous, whereas in the tropics, many species occur as evergreen trees and shrubs.

Their fruits lack endosperm and lie in a scaly or spiny husk that may or may not enclose the entire nut, which may consist of one to seven seeds.

Fagaceae is one of the most ecologically important woody plant families in the Northern Hemisphere, as oaks form the backbone of temperate forest in North America, Europe, and Asia, and are one of the most significant sources of wildlife food.

Many species of oak, chestnut, and beech (genera Quercus, Castanea, and Fagus, respectively) are commonly used as timber for floors, furniture, cabinets, and wine barrels.

Genus-level diversity is concentrated in Southeast Asia,[7] where most of the extant genera are thought to have evolved before migrating to Europe and North America (via the Bering Land Bridge).