Coriander (UK: /ˌkɒrɪˈændər/; US: /ˈkɔːriˌændər/ Coriandrum sativum), also known as cilantro (/sɪˈlɑːntroʊ/) or Chinese parsley, is an annual herb in the family Apiaceae. All parts of the plant are edible, but the fresh leaves and the dried seeds are the parts most traditionally used in cooking.

Coriander grows wild over a wide area of Western Asia and southern Europe, prompting the comment, “It is hard to define exactly where this plant is wild and where it only recently established itself.” Fifteen desiccated mericarps were found in the Pre-Pottery Neolithic B level of the Nehal Hemar Cave in Israel, which may be the oldest archaeological find of coriander. About half a liter (a pint) of coriander mericarps was recovered from the tomb of Tutankhamen, and because this plant does not grow wild in Egypt, Zohary and Hopf interpret this find as proof that coriander was cultivated by the ancient Egyptians.

Coriander seems to have been cultivated in Greece since at least the second millennium BC. One of the Linear B tablets recovered from Pylos refers to the species as being cultivated for the manufacture of perfumes, it apparently was used in two forms: as a spice for its seeds and as a herb for the flavour of its leaves. This appears to be confirmed by archaeological evidence from the same period; the large quantities of the species retrieved from an Early Bronze Age layer at Sitagroi in Macedonia could point to cultivation of the species at that time.

Coriander was brought to the British colonies in North America in 1670, and was one of the first spices cultivated by early settlers.

The fresh leaves are an ingredient in many South Asian foods (such as chutneys and salads); in Chinese and Thai dishes; in Mexican cooking, particularly in salsa and guacamole and as a garnish; and in salads in Russia and other CIS countries. In Portugal, chopped coriander is used in the bread soup Açorda, and in India, chopped coriander is a garnish on Indian dishes such as dal. As heat diminishes their flavour, coriander leaves are often used raw or added to the dish immediately before serving. In Indian and Central Asian recipes, coriander leaves are used in large amounts and cooked until the flavour diminishes. The leaves spoil quickly when removed from the plant, and lose their aroma when dried or frozen.

The dry fruits are known as coriander seeds. The word “coriander” in food preparation may refer solely to these seeds (as a spice), rather than to the plant. The seeds have a lemony citrus flavour when crushed, due to terpenes linalool and pinene. It is described as warm, nutty, spicy, and orange-flavoured. Having a deeper, more intense flavor than the leaves, coriander roots are used in a variety of Asian cuisines, especially in Thai dishes such as soups or curry pastes.

The nutritional profile of coriander seeds is different from the fresh stems or leaves. Leaves are particularly rich in vitamin A, vitamin C and vitamin K, with moderate content of dietary minerals. Although seeds generally have lower content of vitamins, they do provide significant amounts of dietary fiber, calcium, selenium, iron, magnesium and manganese.