The kumquats or cumquats are a family of small fruit-bearing trees in the flowering plant family Rutaceae, in the genus Fortunella which is often included in the genus Citrus. The edible fruit closely resembles that of the orange (Citrus sinensis), but is smaller and is often oval.

They are slow-growing, evergreen shrubs or short trees, from 2.5 to 4.5 metres (8 to 15 ft) tall, with sparse branches, sometimes bearing small thorns. The leaves are dark glossy green, and the flowers pure yellow, similar to other citrus flowers, borne singly or clustered in the leaf-axils. The kumquat tree produces 30 to 50 fruit each year. The tree can be hydrophytic, and fruit is often found floating near the shore during the kumquat season.

Kumquats originated in China (they are noted in literature dating to the 12th century), and have long been cultivated there and in Japan. They were introduced to Europe in 1846 by Robert Fortune, collector for the London Horticultural Society, and shortly thereafter into North America. Originally placed in the genus Citrus, they were transferred to the genus Fortunella in 1915, though subsequent work (Burkill 1931, Mabberley 1998) favours their return to Citrus.