Ann Demeulemeester (born 1959, Waregem, Belgium) is a fashion designer whose eponymous label 'Ann Demeulemeester' is mainly showcased at the annual Paris Fashion Week.

Ann Demeulemeester was born in Waregem, a city in the Flemish province of Belgium in 1959, and later lived in the city of Bruges. Her father, a chicory professor, and her mother both currently live in Waregem. Initially, Demeulemeester showed no interest in fashion. She attended art school for three years, where she discovered her fascination with people and portraiture, which led her to begin thinking about clothing attire. From this, Ann went on to study fashion design at the Royal Academy of Fine Arts in Antwerp from 1978 to 1981. In 1986, Demeulemeester, along with her fellow students from the Antwerp Royal Academy, went to London to showcase their collections. As a result, she is often referred to as a member of the 'Antwerp Six', the radical and distinctive Belgian designers of the 1980s. This group of avant-garde designers are known for their decontructivist styles of creating untraditional clothing lines. Other notables from the group include Dries van Noten and Walter Van Beirendonck.