Mental Floss (stylized mental_floss) is an online magazine and its related American digital, print, and e-commerce media company focused on millennials. It is owned by Minute Media and based in New York City. mentalfloss.com, which presents facts, puzzles, and trivia with a humorous tone, draws 20.5 million unique users a month. Its YouTube channel produces three weekly series and has 1.3 million subscribers. In October 2015, Mental Floss teamed with the National Geographic Channel for its first televised special, Brain Surgery Live with mental_floss, the first brain surgery ever broadcast live.
Launched in Birmingham, Alabama in 2001, the company has additional offices in Midtown Manhattan. The publication was included in Inc. magazine's list of the 5,000 fastest growing private companies. Before it became a web-only publication in 2017, the magazine mental_floss had a circulation of 160,000 and published six issues a year. The magazine had more than 100,000 subscribers in over 17 countries. The November/December 2016 issue was the last issue of the print edition of the magazine. Instead of getting a refund, subscribers were sent copies of The Week.
In 2003 the magazine was product-placed in Friends. In Season 9 episodes 20 and 21 Monica is seen reading a copy in Central Perk.
The company frequently publishes books and sells humorous T-shirts. It also developed a licensed trivia board game called Split Decision, similar to Trivial Pursuit. Its online store sells quirky home and office supplies, games and toys.
Mental Floss was acquired by Minute Media from the Felix Dennis estate in September of 2018. 
The magazine was co-founded by William E. Pearson and Mangesh Hattikudur while they were students at Duke University. According to the Mental Floss website, the idea came from conversations in the Duke cafeteria about the need for an entertaining educational magazine. According to Hattikudur, they wanted to "distill some of the best lectures from our favorite college professors. We thought if we could bottle their enthusiasm and deliver it in monthly installments, it'd be great."
Later, Pearson met with president of Duke University, who loved the idea, but disliked the name. The first published issue, known as the "Campus Edition", was published in spring 2000, distributing 3,000 issues.
The founders spent much of their first year looking for investors and staff members while raising funds to publish the first issue, which was released in May 2001. Over the following summer, 8,000 copies were distributed, and 60% sold out on newsstands.
Mental Floss was sold to magazine mogul Felix Dennis in 2011 and again to Minute Media in late 2018.
Novelist John Green worked for the magazine early in his career. Having later become an established YouTube personality, he began hosting its YouTube channel in March 2013. In 2014, the Mental Floss channel was listed on New Media Rockstars Top 100 Channels, ranked at #71. In 2015, Green won the Webby Award for mental_floss on YouTube.
Kara Kovalchik and Sandy Wood served as research editors for the magazine from 2002-2014. Kara continues to contribute to mentalfloss.com with the 5 Questions Quiz which has appeared each weekday since 2002.
Celebrity chef Alton Brown wrote a food column and appeared on the cover of the September 2012 issue.