Luxo Jr. is the first film produced in 1986 by Pixar Animation Studios, following its establishment as an independent film studio. It is a computer-animated short film (two and a half minutes, including credits), demonstrating the kind of things the newly-established company was capable of producing. It was the second Pixar short to release with a Pixar film (Toy Story 2) after Geri's Game was released with A Bug's Life in 1998.

It is the source of the small hopping desk lamp included in Pixar's corporate logo. In a subsequent re-release after Pixar became popular, a pretext was added to the film reading, "In 1986 Pixar produced its first film. This is why we have a hopping lamp in our logo."

The only characters are two Anglepoise desk lamps, one large and one small, inspired by a Luxo brand task-light on John Lasseter's desk (hence the title). Luxo Jr. (small) and a bigger lamp are playing with a small inflated rubber ball, chasing it and trying to balance on it, as Luxo (large) reacts to these antics. The ball eventually deflates due to Luxo Jr. jumping on it; Luxo Jr. is admonished by Luxo, who then finds Luxo Jr. playing with an even larger ball, as Luxo just wonders.