Cosmos sulphureus is a species of flowering plant in the sunflower family Asteraceae, also known as sulfur cosmos and yellow cosmos. It is native to Mexico, Central America, and northern South America, and naturalized in other parts of North and South America as well as in Europe, Asia, and Australia. It was introduced into Asia from Mexico via the Manila-Acapulco galleon trade.

This plant was declared invasive by the United States Southeast Exotic Pest Plant Council in 1996. The flowers of all Cosmos attract birds and butterflies, including the monarch butterfly.

The original and its cultivars appear in shades of yellow, orange, and red. It is especially popular in Korea and Japan, where it is often seen in mass plantings along roadsides, following an initiative pursued by the Korean-Japanese botanist Woo Jang-choon.