Which Lego video game is set in the world of The Lord of the Rings?

The Lego video game set in the world of The Lord of the Rings is Lego The Lord of the Rings.

Released in 2012, the action-adventure game was developed by Traveller's Tales and published by Warner Bros. Interactive Entertainment. It adapts the storylines of all three films in Peter Jackson's trilogy: The Fellowship of the Ring, The Two Towers, and The Return of the King.

Players explore a Lego version of Middle-earth, controlling characters such as Frodo, Gandalf, Aragorn, Legolas, Gimli, and Gollum. Each character has abilities suited to particular puzzles, while collectible items and weapons add extra gameplay layers. The game includes 18 main story levels, six based on each film, plus a bonus level.

The answer is sometimes confused with Lego The Hobbit, another Middle-earth game. Lego The Hobbit covers events from the Hobbit films, not The Lord of the Rings trilogy. Lego The Lord of the Rings is therefore the single canonical answer.