1991

The following events occurred in the year 1991:

Unknown

 * Harry Potter finishes at his Muggle Primary School, at the age of ten.
 * Charlie Weasley and Nymphadora Tonks graduate from Hogwarts School of Witchcraft and Wizardry.
 * A Wizardry Budget is leaked and makes Daily Prophet headlines.

June

 * 23 June: For Dudley Dursley's eleventh birthday, his parents, cousin Harry Potter, and Piers Polkiss go to the zoo. Harry speaks Parseltongue for the first time to a boa constrictor.

July

 * 24 July: Harry Potter receives his first Hogwarts letter. Vernon and Petunia Dursley burn it. Harry's bedroom is moved from the Cupboard under the stairs to Dudley's second bedroom.
 * 31 July: Quirinus Quirrell breaks into Gringotts Wizarding Bank, but fails to steal the Philosopher's Stone. Harry, on his eleventh birthday, goes to Diagon Alley for the first time with Rubeus Hagrid.

September

 * 1 September: Harry Potter and his classmates – including Ron Weasley, Hermione Granger, Neville Longbottom, and Draco Malfoy – begin at Hogwarts.
 * 12 September: Harry Potter becomes the youngest Seeker in a century for the Gryffindor Quidditch team.

October

 * 31 October: During the Halloween feast at Hogwarts, a mountain troll is let loose by Professor Quirrell, who looks for the Philosopher's Stone. Harry Potter and Ron Weasley save Hermione Granger from the troll, and the three become friends.

November

 * Harry plays his first Quidditch match.

December

 * 25 December: Harry receives his late father's Invisibility Cloak from Albus Dumbledore as a Christmas present. He also finds the Mirror of Erised and sees his family for the first time.

Gryffindor

 * Lavender Brown<ref name="pottermore"/
 * Seamus Finnigan
 * Hermione Granger
 * Neville Longbottom
 * Parvati Patil
 * Harry Potter
 * Dean Thomas
 * Ronald Weasley

Hufflepuff

 * Hannah Abbott
 * Susan Bones
 * Justin Finch-Fletchley
 * Wayne Hopkins
 * Megan Jones
 * Ernie Macmillan

Ravenclaw

 * Terry Boot
 * Mandy Brocklehurst
 * Michael Corner
 * Anthony Goldstein
 * Sue Li
 * Morag MacDougal
 * Padma Patil
 * Lisa Turpin

Slytherin

 * Millicent Bulstrode
 * Vincent Crabbe
 * Tracey Davis
 * Gregory Goyle
 * Daphne Greengrass
 * Draco Malfoy
 * Theodore Nott
 * Pansy Parkinson
 * Blaise Zabini

Unknown

 * Stephen Cornfoot (Hufflepuff or Ravenclaw)
 * Kevin Entwhistle (Hufflepuff or Ravenclaw)
 * Roger Malone (Hufflepuff or Ravenclaw)
 * Lily Moon (Hufflepuff or Slytherin)
 * Oliver Rivers (Hufflepuff or Ravenclaw)
 * Sally-Anne Perks (Gryffindor, Hufflepuff or Slytherin)
 * Sophie Roper (Gryffindor, Hufflepuff or Slytherin)
 * Runcorn (Gryffindor, Hufflepuff or Slytherin)
 * Sally Smith (Gryffindor, Hufflepuff or Slytherin)

Individuals who gathered from Hogwarts

 * Charles Weasley
 * Nymphadora Tonks

Deaths

 * Arcturus Black III
 * Magenta Comstock
 * Perpetua Fancourt
 * Tilly Toke

Behind the scenes

 * 17 February: Bonnie Wright, the actress who portrays Ginny Weasley in the Harry Potter films, is born.
 * April 21: Frank Dillane, the actor who portrays young Tom Riddle in the film adaptation of Harry Potter and the Half-Blood Prince, is born.
 * 16 August: Evanna Lynch, the actress who portrays Luna Lovegood in the Harry Potter films, is born.
 * 18 October: Toby Regbo, the actor who portrays a Young Albus Dumbledore in the Harry Potter films is born.
 * 13 January: Genevieve Gaunt, the actress who portrays Pansy Parkinson in the film adaptation of Harry Potter and the Prisoner of Azkaban, is born.