Lego Harry Potter: Years 1–4

Lego Harry Potter: Years 1–4 is a Lego-themed action-adventure video game developed by Traveller's Tales and published by Warner Bros. The game is based on the Lego Harry Potter line and its storyline covers the first four films in the Harry Potter series: Harry Potter and the Sorcerer's Stone, Harry Potter and the Chamber of Secrets, Harry Potter and the Prisoner of Azkaban, and Harry Potter and the Goblet of Fire. The game is available on the Wii, Xbox 360, PlayStation 3, Nintendo DS, PlayStation Portable, Microsoft Windows, OS X, iOS and Android. The OS X version of the game was released on 22 February 2011 by Feral Interactive. The game was released for the PlayStation 4 on October 21, 2016, as part of the Lego Harry Potter Collection, which bundles the game with its sequel, Lego Harry Potter: Years 5–7.

Lego Harry Potter's gameplay is similar to that of most previous Lego video games, with an emphasis on collecting, exploring, and solving puzzles. Casting spells is an integral part of the gameplay, with a wide range of spells available for unlocking as the player progresses. As there are many spells available in the game, the player can use the spell wheel to select the spell. Potion-making is another integral feature; potions can help the player complete levels or, if created incorrectly, have adverse side effects such as turning the player into a frog.

The central hub is Diagon Alley and its entrance through the Leaky Cauldron. Players can access a room at the second floor of the building to watch videos from the game, as well as using a notice board with pictures from where the player can play completed levels again. Diagon Alley serves as a series of stores where the player is able to buy characters or change a number of customizable ones, spells, and bricks that have a varying range of uses.