Nichijou (Japanese: 日常, Hepburn: Nichijō, lit. "Everyday") is a Japanese manga series written and illustrated by Keiichi Arawi. The manga began serialization in the December 2006 issue of Kadokawa Shoten's manga magazine Shōnen Ace, and was also serialized in Comptiq between the March 2007 and July 2008 issues. Kadokawa Shoten later published all chapters of the series' initial run in ten tankōbon volumes from July 2007 to December 2015. After a six-year hiatus, the manga began serialization again in 2021.Set in a typical suburban Japanese town, Nichijou is populated by an ensemble set of characters, featuring moments from their everyday lives which alternate between the mundane and the strange, without strong focus on a narrative. A 26-episode anime television series directed by Tatsuya Ishihara and produced by Kyoto Animation was broadcast on independent television stations from April 3 to September 21, 2011, after an earlier original video animation (OVA) was released in March. A PlayStation Portable game by Vridge and Kadokawa Shoten was released on July 28, 2011, entitled Nichijou: Uchuujin.

The manga and anime series were initially licensed in North America by Bandai Entertainment in July 2011, but both releases were cancelled due to the company's downsizing. The manga series was later licensed for publication in English by Vertical, with the first volume released in March 2016. Funimation released the anime in North America with subtitles on Blu-ray Disc and DVD on February 7, 2017. An English dub was later created for the Blu-ray re-release on July 23, 2019. Madman Entertainment licensed the anime series in 2011 for Australian and New Zealand distribution, releasing the DVDs in April and May 2013.

The anime adaptation initially received reserved praise from Western critics, who commended the animation quality but found it lacking in consistent humor and substance. Retrospective reviews, however, have since given the series high critical praise for its heart and surreal comedy, with one critic deeming it among the "finest anime comedies of all time".