Cosmos is a genus, with the same common name of cosmos, consisting of flowering plants in the daisy family.

The generic name Cosmos derives either from the Greek κόσμος (cosmos) '(ordered) world' – in reference to the neat, orderly arrangement of the floral structures – or the Greek κόσμημα (kósmima) 'jewel' – in reference to the jewel-like colors of the capitula (composite flowers).

Cosmos are herbaceous perennial plants or annual plants growing 0.3–2 metres (1–6+1⁄2 ft) tall. The leaves are simple, pinnate, or bipinnate, and arranged in opposite pairs. The flowers are produced in a capitulum with a ring of broad ray florets and a center of disc florets; flower color varies noticeably between the different species. The genus includes several ornamental plants popular in gardens. Numerous hybrids and cultivars have been selected and named.

Kew's Plants of the World Online accepts 35 species, with the Compositae Working Group listing two more.

Cosmos species are native to scrub and meadowland in the Americas, from Colorado and Missouri in the United States, extending south through Mexico (where highest species diversity occurs, with 33 of the 35 species) and Central America to South America as far south as northern Argentina.

One species, C. bipinnatus, is naturalized across much of the eastern U.S. and eastern Canada. The genus is also widespread over the high eastern plains of South Africa, where it was introduced via contaminated horsefeed during the Anglo-Boer War.

Cosmos caudatus and C. sulphureus are edible and a major part of salads eaten as appetizers before meals in Maritime Southeast Asia including the Malay ulam and the Sundanese lalab.