The sunflower (Helianthus annuus) is an annual plant in the Asteraceae Family, with a large flower head (inflorescence). The stem of the flower can grow up to 3 metres tall, with the flower head reaching 30cm in diameter.

Sunflowers are native to the Americas, Francisco Pizarro found the Incas venerating the sunflower as an image of their sun god. Gold images of the flower, as well as seeds, were taken back to Europe early in the 16th century. Helianthus is the Greek word for "sunflower".

In Greek mythology, a girl named Clytie fell in love with the sun god Apollo, and would do nothing but watch his chariot move across the sky. After nine days, she was transformed into a sunflower. However, the word "sunflower" and its cognates existed long before Helianthus annuus was brought to Europe, and it is thought that the myth (which is mentioned in Ovid's poem Metamorphoses) actually refers to heliotrope or marigold.

The sunflower is the state flower of the U.S. state of Kansas, and one of the city flowers of Kitakyushu, Japan.