Camellia japonica (the Japanese camellia) is one of the best known species of the genus Camellia. Sometimes called the Rose of winter, it belongs to the Theaceae family. It is the official state flower of Alabama. There are thousands of cultivars of C. japonica in cultivation, with many different colors and forms of flowers.

In the wild, it is found in mainland China (Shandong, east Zhejiang), Taiwan, southern Korea and southern Japan.It grows in forests, at altitudes of around 300–1,100 metres (980–3,610 ft).

Camellia japonica is a flowering tree or shrub, usually 1.5–6 metres (4.9–19.7 ft) tall, but occasionally up to 11 metres (36 ft) tall. Some cultivated varieties achieve a size of 72m² or more. The youngest branches are purplish-brown, becoming grayish-brown as they age. The alternately arranged leathery leaves are dark green on the top side, paler on the underside, usually 5–11 centimetres (2.0–4.3 in) long by 2.5–6 centimetres (1.0–2.4 in) wide with a stalk (petiole) about 5–10 millimetres (0.2–0.4 in) long. The base of the leaf is pointed (cuneate), the margins are very finely toothed (serrulate) and the tip somewhat pointed.

In the wild, flowering is between January and March. The flowers appear along the branches, particularly towards the ends, and have very short stems. They occur either alone or in pairs, and are 6–10 centimetres (2.4–3.9 in) across. There are about nine greenish bracteoles and sepals. Flowers of the wild species have six or seven rose or white petals, each 3–4.5 centimetres (1.2–1.8 in) long by 1.5–2.5 centimetres (0.6–1.0 in) wide; the innermost petals are joined at the base for up to a third of their length. (Cultivated forms often have more petals.) The numerous stamens are 2.5–3.5 centimetres (1.0–1.4 in) long, the outer whorl being joined at the base for up to 2.5 centimetres (1.0 in). The three-lobed style is about 3 centimetres (1.2 in) long.

The fruit consists of a globe-shaped capsule with three compartments (locules), each with one or two large brown seeds with a diameter of 1–2 centimetres (0.4–0.8 in). Fruiting occurs in September to October in the wild.

C. japonica leaves are eaten by the caterpillars of some Lepidoptera, such as The Engrailed (Ectropis crepuscularia). The Japanese white eye bird (Zosterops japonica) pollinates Camellia japonica.