- Cormac McLaggen — a Gryffindor student who attended Hogwarts School of Witchcraft and Wizardry in the 1990s.
- Mr McLaggen — father of Cormac.
- Tiberius, a friend of Bertie Higgs and Rufus Scrimgeour, was an uncle of Cormac McLaggen, but it is unknown on what side of the family and whether through blood or marriage.
J. K. Rowling revealed that she discovered the surname while writing Harry Potter and the Half-Blood Prince and felt compelled to use it for a character because she thought it was "too good to waste".
- Harry Potter and the Half-Blood Prince (First appearance)
- Harry Potter and the Half-Blood Prince (film)
- Harry Potter and the Half-Blood Prince (video game)
- Harry Potter and the Deathly Hallows: Part 1 (video game)
- Harry Potter and the Deathly Hallows: Part 2 (video game)
- Pottermore (Mentioned only)
- Wizarding World (Mentioned only)
- LEGO Harry Potter: Years 5-7
- Harry Potter: The Character Vault