Willem van Haecht, sometimes also Willem van Haecht the elder to distinguish him from the painter Willem van Haecht was a Flemish poet writing in the Dutch language. He was also a cloth merchant, draughtsman, a bookseller and publisher. He was a member since 1552 and from 1558 a factor of the chamber of rhetoric De Violieren in Antwerp. In that role he played an important part in the transition of the development of theatre in Flanders from plays mainly dealing with epic, moralising or allegorising themes towards plays expressing the humanist ideas of the Renaissance. He published the Psalms of the Bible in Dutch verse and also wrote poems and songs.

The Violieren was a chamber of rhetoric that dates back to the 15th century in Antwerp, when it was a social drama society with close links to the Guild of Saint Luke. It was one of three drama guilds in the city, the other two being the Goudbloem and the Olyftack. In 1660 the Violieren merged with former rival Olyftack, and in 1762 the society was dissolved altogether.