Professor Dilys Derwent (d. 1768) was a witch who worked as a Healer at St Mungo's Hospital for Magical Maladies and Injuries (1722-1741), and was a celebrated Headmistress of Hogwarts School of Witchcraft and Wizardry (1741-1768). Her portrait hangs not only in the Headmaster's Office along with the portraits of previous headmasters and headmistresses, but also in St Mungo's Hospital for Magical Maladies and Injuries' main admitting area.