Osmanthus ( /ɒzˈmænθəs/) is a genus of about 30 species of flowering plants in the family Oleaceae, mostly native to warm temperate Asia (from the Caucasus east to Japan) but one species (O. americanus) occurring in North America (southeastern United States, Texas to Virginia). It is sometimes included in Nestegis. They range in size from shrubs to small trees, 2-12 m tall. The leaves are opposite, evergreen, and simple, with an entire, serrated or coarsely toothed margin. The flowers are produced in spring, summer or autumn, each flower being about 1 cm long, white, with a four-lobed tubular-based corolla ('petals'). The flowers grow in small panicles, and in several species have a strong fragrance. The fruit is a small (10-15 mm), hard-skinned dark blue to purple drupe containing a single seed.

Osmanthus are popular shrubs in parks and gardens throughout the warm temperate zone. Several hybrids and cultivars have been developed. In China, osmanthus tea (Chinese: 桂花茶; pinyin: guìhuā chá) is produced by combining dried Sweet Osmanthus (Osmanthus fragrans) flowers (Chinese: 桂花; pinyin: guìhuā) with black or green tea leaves in much the same manner the more familiar jasmine tea combines jasmine flowers with tea leaves. In Japan, Osmanthus asiaticus or Sweet Olive is a favourite garden shrub. Known as Gin-mokusei, its small white flowers appear in short stalked clusters in late autumn. It has an intense sweet fragrance which has been described as a blend of jasmine, gardenia and ripe apricots. Another variant popular in Japan is Osmanthus aurantiacus, also known as Kin-mokusei. Very similar to the Sweet Olive but has deep, golden flowers.