Ayu is the nickname of Ayumi Hamasaki, a Japanese pop singer.

Ayumi Hamasaki (浜崎 あゆみ, Hamasaki Ayumi?, also 浜崎 歩) (born October 2, 1978) is a Japanese singer-songwriter and former actress. Also called Ayu by her fans, Hamasaki has been dubbed the "Empress of Pop" due to her popularity and widespread influence in Japan. Born and raised in Fukuoka, she moved to Tokyo at fourteen to pursue a career in entertainment. In 1998, under the tutelage of Avex CEO Max Matsuura, she released a string of modestly selling singles that concluded with her 1999 debut album A Song for XX. The album debuted atop the Oricon charts and stayed there for four weeks, establishing her popularity in Japan.

Because of her constantly changing image and tight control over her artistry, Hamasaki's popularity extends across Asia; music and fashion trends she has started have spread to countries such as China, Singapore, and Taiwan.