This is the class of magic that changes one object into another. It is commonly known that this is some of the most complex and dangerous magic that is known in the Wizarding World. Those who are able to perform certain feats, Animagi for example, are required to register with the Ministry of Magic. Transfiguration is a required course in Hogwarts from the first to the fifth year, after which point it may be taken until the seventh year as an elective.

First year: Students are taught the very rudiments of Transfiguration, temporarily switching objects about that are similar in appearance. An example of this would be matchsticks into needles or beetles into buttons. At this point, coursework focuses mainly on Transfiguring objects that are small, look alike and often begin with the same letter.

Second year: Study in the basics of Transfiguration continues, with coursework including changing porcupines into pin cushions. Work is restricted to objects that are moderately small, similar in size and begin with the same letter. Students also continue to work on changing inanimate or animate objects into inanimate.

Third year: Basic Transfiguration studies continue, however students are introduced to changing inanimate objects into animate creatures. An example of this would be changing a tea kettle into a turtle.

Fourth year: Intermediate Transfiguration studies begin, with review of the basics. Coursework includes essays and attending lectures, and practicals will involve changing species of animals (ie, a guinea hen into a guinea pig) and changing features of one object for that of another (ie, changing an animal's teeth into piano keys).

Fifth year: Studies focus primarily on Transfiguring large objects and objects which have no relation to each other in the Wizarding sense (objects which do not share a similar appearance or name). Examples would be changing a desk into a pig or changing a praying mantis into a walrus. Conjuration is introduced. Students also do review of the first years' coursework in preparation for the OWLs.

For the OWLs: Students are expected to demonstrate, through essays and practicals, their understanding of all concepts studied since the first year of school. They will be required to Transfigure a variety of inanimate and animate objects.

Sixth year: The studies of advanced Transfiguration students focus on human subjects. It is very complex magic, taking the entirety of the year to be able to achieve partial human Transfiguration. Effects are temporary, lasting up to an hour at most. Also during this time, students fine-tune work on their Conjuration and Dispelling of objects.

Seventh year: Studies of human Transfiguration continue, and preparation for the NEWTs is included with the coursework. At the conclusion of the year, students are expected to be able to Transfigure a human fully into another animal. The effects are temporary, wearing off after an hour or so despite any effort made on the part of the Wizard or victim to remain in an animal state.

For the NEWTs: Students must demonstrate their understanding of the theories behind Animagus transformation through essays, and through practicals they must demonstrate their ability to perform full and partial human Transfiguration.