It's Such a Beautiful Day is a 2012 American experimental animated comedy-drama film written, directed, animated, photographed, produced, and narrated by Don Hertzfeldt. It follows Bill, a stick figure who struggles with memory loss and surreal visions, among other symptoms of an unknown neurological problem.

The film employs both offbeat humor and philosophical musings. It mostly consists of stick figures with stylized real-life footage appearing in many split-screen windows that are photographed through multiple exposures. The film is divided into three chapters, all of which were originally released in theaters as animated short films: Everything Will Be OK (2006), I Am So Proud of You (2008), and It's Such a Beautiful Day (2011). The three short films collectively received over 90 film festival awards upon their original releases, including the Sundance Film Festival's Grand Prize for Everything Will Be OK. In 2012, the three chapters were combined and released as a new feature film.

It's Such a Beautiful Day received widespread critical acclaim, with its experimental storytelling and surreal elements being singled out for praise. Many listed it as one of the best films of 2012, and it has since come to be widely regarded as one of the greatest animated films of all time.