QI (Quite Interesting) is a British comedy panel game quiz show for television created and co-produced by John Lloyd. The series currently airs on BBC Two and is presented by Sandi Toksvig. It features permanent panellist Alan Davies and three guest panellists per episode; the panellists are mostly comedians. The series was presented by Stephen Fry from its beginning in 2003 until 2016.The format of the show focuses on the panellists answering questions that are extremely obscure, making it unlikely that the correct answer will be given. To compensate, the panellists are awarded points not only for the correct answer, but also for interesting ones, regardless of whether they are correct or even relate to the original question, while points are deducted for "answers which are not only wrong, but pathetically obvious" – typically answers that are generally believed to be true but in fact are misconceptions. These answers, referred to as "forfeits", are usually indicated by a loud klaxon and alarm bell, flashing lights, and the incorrect answer being flashed on the video screens behind the panellists. Bonus points are sometimes awarded or deducted for challenges or incorrect references, varying from show to show. QI has a philosophy that "everything is interesting if looked at in the right way". Many factual errors in the show have been corrected in later episodes or on the show's blog.

For its first five series shown between 2003 and 2007, episodes premiered on BBC Four before receiving their first analogue airing on BBC Two a week later. From 2008 to 2011, the show was moved to BBC One, with an extended-length edition of each episode often broadcast on BBC Two a day or two after the regular show's broadcast under the title of QI XL. Series G and H saw the regular show broadcast in a pre-watershed slot with the extended edition remaining within a post-watershed slot. Beginning with the I series, the regular show returned to a post-watershed slot on BBC Two. Syndicated episodes of previous series are regularly shown on Dave. In November 2020 a new compilation series titled QI XS started, with a run-time of 14 minutes per episode. A second series of XS, with an 8-minute running time, started in February 2023. Series of QI are assigned letters in sequence and episodes are themed around topics starting with that letter.

The show has received very positive ratings from critics and has been nominated for multiple awards; QI itself has the highest viewing figures for any show broadcast on BBC Two and Dave. Several books, DVDs and other tie-ins to the show have been released, and international versions of QI have been made in other countries.