Headmaster

A Headmaster or Headmistress is the chief administrator of a School of Magic. They make all major decisions regarding the safety and the day-to-day functioning of the school, and have the power to override any decision made by any other authoritative facilitator at the school. A Headmaster also controls the protective spells surrounding the school and the ability for certain individuals to enter or exit the grounds at will.

Hogwarts School of Witchcraft and Wizardry
Known Headmasters of Hogwarts School of Witchcraft and Wizardry:
 * Godric Gryffindor (Medieval times)
 * Helga Hufflepuff (Medieval times)
 * Rowena Ravenclaw (Medieval times)
 * Salazar Slytherin (Medieval times)
 * Professor Nutpus
 * Professor Everard (sometime in the early 17th century)
 * Dilys Derwent (1741-1768)
 * Phineas Nigellus Black
 * Dexter Fortescue
 * Heliotrope Wilkins
 * Newt Scamander (sometime in the early 20th century)
 * Armando Dippet(1925-1956)
 * Albus Dumbledore (1956-1993)
 * Minerva McGonagall (Acting)(1993)
 * Albus Dumbledore (1993-1996)
 * Dolores Umbridge (1996)
 * Albus Dumbledore (1996-1997)
 * Severus Snape (1997-1998)
 * Minerva McGonagall (1998-2017)

Durmstrang Institute
Known Headmasters of Durmstrang Institute:
 * Igor Karkaroff (Unknown-1995)

Beauxbatons Academy of Magic
Known Headmasters of Beauxbatons Academy of Magic:
 * Olympe Maxime