Breitbart News Network (/ˈbraɪtbɑːrt/; known commonly as Breitbart News, Breitbart, or Breitbart.com) is an American far-right news, opinion, and commentary website founded in 2007 by American conservative commentator Andrew Breitbart. Its content has been described as misogynistic, xenophobic, and racist by various academics and journalists. The site has published a number of conspiracy theories and intentionally misleading stories, as well as having promoted climate change denial and COVID-19 misinformation. Posts originating from the Breitbart News Facebook page are among the most widely shared political content on Facebook.

Initially conceived as "the Huffington Post of the right", Breitbart News later aligned with the alt-right, the European populist right, and the pan-European nationalist identitarian movement under the management of former executive chairman Steve Bannon, who declared the website "the platform for the alt-right" in 2016. Breitbart News became a virtual rallying spot for supporters of Donald Trump's 2016 presidential campaign. The company's management, together with former staff member Milo Yiannopoulos, solicited ideas for stories from, and worked to advance and market ideas of neo-Nazi and white supremacist groups and individuals. After the election, more than 2,000 organizations removed Breitbart News from ad buys following Internet activism campaigns denouncing the site's controversial positions. Breitbart's monthy visitors continually declined after Trump's election, from 17.3 million monthly readers at the beginning of 2017 to 4.6 million in May 2019 and to around 700,000 monthly readers in 2024.

The company is headquartered in Los Angeles, with bureaus in Texas, London, and Jerusalem. Co-founder Larry Solov is the co-owner (along with Andrew Breitbart's widow Susie Breitbart and the Mercer family) and CEO. Alex Marlow is the editor-in-chief, Wynton Hall is managing editor, and Joel Pollak and Peter Schweizer are senior editors-at-large.

Andrew Breitbart launched Breitbart.com as a news aggregator in 2005. The website featured direct links to wire stories at the Associated Press, Reuters, Fox News, the New York Post, TMZ as well as a number of other outlets. The website's initial growth was largely fueled by links from the Drudge Report. In 2007, Breitbart.com launched a video blog, Breitbart.tv.

According to co-founder Larry Solov, the two men were in agreement that the site should be "unapologetically pro-freedom and pro-Israel" during their visit to Israel in 2007. In August 2010, Andrew Breitbart told the Associated Press that he was "committed to the destruction of the old media guard." As part of that commitment, he founded Breitbart.com, a website designed to become "the Huffington Post of the right" according to Breitbart News's former executive chairman, Steve Bannon. Breitbart News exclusively re-posted the Anthony Weiner sexting scandal, the resignation of Shirley Sherrod, and the ACORN 2009 undercover videos controversy. Following Andrew Breitbart's death in 2012, the site was redesigned, bringing the formerly distinct "Big" websites under one umbrella website at Breitbart.com.

Billionaire conservative activist Robert Mercer endowed Breitbart.com with at least $11 million in 2011.

Andrew Breitbart died in March 2012. The website hosted a number of memorials for him. Editors said they intended to carry on his legacy at the website. Following Andrew Breitbart's death, former board member Steve Bannon became executive chairman and Laurence Solov became CEO. The company also hired Joel Pollak as editor-in-chief and Alex Marlow as managing editor. An October 2012 article in BuzzFeed News suggested there were internal tensions in the organisation in the year after Andrew Breitbart's death as staffers battled for ownership of his legacy.

Before his death, Andrew Breitbart had begun a redesign of the Breitbart News website to transform it from a links-aggregator into a more tabloid-style website. The redesign was launched shortly after his death in March 2012.