Felix Arvid Ulf Kjellberg (; SHEL-burg, Swedish: [ˈfěːlɪks ˈǎrːvɪd ɵlf ˈɕɛ̂lːbærj] ; born 24 October 1989), better known as PewDiePie (; PEW-dee-py), is a Swedish YouTuber known for his comedic videos. Kjellberg's popularity on YouTube and extensive media coverage has made him one of the most noted online personalities and content creators. He has been portrayed in media as a figurehead for YouTube, especially in the genre of gaming.

Born and raised in Gothenburg, Kjellberg registered his YouTube channel "PewDiePie" in 2010, primarily posting Let's Play videos of horror and action video games. His channel gained a substantial following and was one of the fastest growing channels in 2012 and 2013, before becoming the most-subscribed on YouTube on 15 August 2013. From 29 December 2014 to 14 February 2017, Kjellberg's channel was also the most-viewed on the platform. During this period, his content shifted focus from Let's Plays and diversified to include vlogs, comedy shorts, formatted shows, and music videos.

Kjellberg's content was already noted for its polarizing reception among general audiences online, but in the late 2010s, it became more controversial and attracted increased media scrutiny. In 2019, following a public competition with Indian record label T-Series, Kjellberg was overtaken as the most-subscribed YouTube channel. Kjellberg also became more reserved online, uploading less consistently and taking frequent breaks from Internet use. He eventually semi-retired from YouTube, choosing to upload less frequently for his enjoyment rather than as a career. Meanwhile, in his personal life, he moved to Japan with his wife, Italian Internet personality Marzia.

With over 111 million subscribers and 29.3 billion views, his channel still ranks as one of the most-subscribed and viewed on YouTube. His popularity online has been noted to boost sales for the video games he plays, and has allowed him to stir support for charity fundraising drives. In 2016, Time magazine named him as one of the world's 100 most influential people.