The Cupboard Under the Stairs was Harry Potter's room in the Dursley household until he was given Dudley Dursley's old room, at 4 Privet Drive in Little Whinging, Surrey. The cupboard was described as small and dusty, with lots of spiders.
When Harry's mother and father were killed in 1981, Harry was brought to his maternal aunt, Petunia Dursley. She and her husband Vernon reluctantly took him in, but treated him poorly, mostly because his parents had been magical and they feared that Harry would also turn out to be a "freak". Instead of being given a real bedroom, Harry was kept in the cupboard under the stairs. Harry's cousin Dudley is roughly the same age and used to jump up and down on top of these stairs so sawdust would fall onto Harry.
In addition to sleeping in the cupboard and keeping his possessions, it also served as a place for the Dursleys to punish Harry every time he accidentally unleashed some magic. On one occasion, Aunt Petunia gave Harry an awful haircut, but his hair grew back quickly the next day, resulting in Harry getting a week in his cupboard. After an incident involving levitation on to the school roof, Harry was locked in his cupboard for a longer period. Uncle Vernon threatened Harry that he would be in the cupboard from June until Christmas, but after the escape of the boa constrictor on Dudley's 11th birthday, Harry got a lengthy punishment in the cupboard until the summer holidays.
The Dursleys' fears about Harry being magical turned out to be correct, as Harry received an invitation to attend Hogwarts School of Witchcraft and Wizardry in 1991. The first letter was addressed: Mr H Potter The Cupboard under the stairs. This prompted the Dursleys to allow Harry to move into what had previously been Dudley's second bedroom. Despite the Dursleys' numerous attempts to prevent Harry from accepting the offer, he soon went to Hogwarts. From 1992 onwards, Harry slept in Dudley's second bedroom and the cupboard was used by the Dursleys to store Harry's magical possessions while he was staying with them during the summer holidays, until the Dursleys learned of Sirius Black's existence and no longer made Harry hide his things there.
- Harry Potter and the Philosopher's Stone (First appearance)
- Harry Potter and the Philosopher's Stone (film)
- Harry Potter and the Chamber of Secrets (film) (Door only)
- Harry Potter and the Prisoner of Azkaban
- Harry Potter and the Prisoner of Azkaban (film) (Door only)
- Harry Potter and the Goblet of Fire (film) (Indirectly mentioned)
- Harry Potter and the Order of the Phoenix (film) (Door only)
- Harry Potter and the Half-Blood Prince (film) (Mentioned only)
- Harry Potter and the Deathly Hallows
- Harry Potter and the Deathly Hallows: Part 1
- Harry Potter and the Cursed Child (Appears in dream)
- Harry Potter and the Cursed Child (play) (Appears in dream)
- LEGO Harry Potter: Years 1-4
- LEGO Harry Potter: Years 5-7 (Door only)