Theobroma cacao, also called the cocoa tree and the cacao tree, is a small (4–8 m (13–26 ft)) evergreen tree of the family Malvaceae, native to the deep tropical regions of Mesoamerica. Its seeds, cocoa beans, are used to make chocolate liquor, cocoa solids, cocoa butter, and chocolate. The largest producer of cocoa beans in 2018 was Côte d'Ivoire, with 37% of the world total.

The leaves are alternate, entire, not smooth, 10–40 cm (3.9–15.7 in) long and 5–20 cm (2.0–7.9 in) broad.

The flowers are produced in clusters directly on the trunk and older branches; this is known as cauliflowering. The flowers are small, 1–2 cm (0.39–0.79 in) in diameter, with a pink calyx. The floral formula, used to represent the structure of a flower using numbers, is ✶ K5 C5 A (5° + 5²) G (5). While many of the world's flowers are pollinated by bees (Hymenoptera) or butterflies/moths (Lepidoptera), cocoa flowers are pollinated by small flies, Forcipomyia midges in the subfamily Forcipomyiinae. Using the natural pollinator of Forcipomyia midges for Theobroma cacao has been shown to produce more fruit than the artificial pollinator. The fruit, called the cocoa pod, is ovoid, 15–30 cm (5.9–11.8 in) long and 8–10 cm (3.1–3.9 in) wide, ripening from yellow to orange, and weighing about 500 g (1.1 lb) mature. The pod contains 20 to 60 seeds, usually called “beans,” embedded in a white pulp. The seeds are the main ingredient in chocolate, while the pulp is used in some countries to make refreshing juice, smoothies, jelly, and cream. Usually discarded until practices changed in the 21st century, the fermented pulp can be distilled into an alcoholic beverage. Each seed contains a significant amount of fat (40–50%) as cocoa butter. The active constituent of the fruit is the stimulant theobromine, a caffeine-like compound.