Professor Minerva McGonagall teaches Transfiguration in J.K. Rowling’s Harry Potter novels.
Transfiguration is the branch of magic concerned with changing the form or appearance of an object or person. McGonagall is the Transfiguration professor at Hogwarts and is also the head of Gryffindor House for much of the series.
She first appears as a strict but fair teacher who can transform into a cat. Her lessons include demanding practical work, and she expects precision from students. McGonagall’s role expands as the story progresses: she becomes deputy headmistress, later serves as headmistress, and participates in the defence of Hogwarts.
Transfiguration is distinct from Charms, which adds properties or actions without fundamentally changing an object’s nature. It is also separate from Potions, which uses ingredients and brewing rather than direct spellwork.