Pentatonix (or PTX) is an American a cappella group consisting of five vocalists originating from Arlington, Texas. The members in this group are Avi Kaplan, Scott Hoying, Kirstin Maldonado, Kevin Olusola, and Mitch Grassi. Their work, which is mostly in the pop style, consists of covers of existing songs, sometimes in the form of medleys, along with original material. Their music is defined by their own arrangement style, tight vocal harmonies, extensive vocal riffing, deep and steady vocal basslines, and a diverse range of vocal percussion and beatboxing.

Pentatonix formed in 2011 and came to prominence the same year by winning the third season of The Sing-Off on NBC, their victory earning them $200,000 and a recording contract with Sony Music. After being dropped from the label (Epic Records) after The Sing-Off, the group formed their popular YouTube channel and distributed their music through Madison Gate Records, a small independent label owned by Sony Pictures that distributes movie soundtracks. The group also made effective use of social media to interact with their fan base. Having now eclipsed 9 million subscribers and more than 1 billion cumulative views, the PTXofficial YouTube page is currently the 13th-most subscribed-to music channel and the 44th-most subscribed channel overall. Pentatonix's most viewed music video is a tribute to Daft Punk that recently surpassed 150 million views.

Their debut EP PTX, Volume 1 was released in 2012, followed by PTXmas the same year, with their third release, PTX, Vol. II, debuting at number 1 on Billboard‍ '​s Independent Albums chart and number 10 on the Billboard 200 in 2013. In May 2014, Pentatonix signed with RCA Records, a "flagship" label of Sony Music Entertainment. In the same year, the group released their fourth EP, PTX, Vol. III, and two full-length studio albums, PTX, Vols. 1 & 2 (a compilation album released in Japan, Korea and Australia) and their second holiday release, That's Christmas to Me. That's Christmas to Me was certified gold by the Recording Industry Association of America (RIAA), and platinum on December 24, 2014, becoming the highest-charting holiday album by a group since 1962, and the fourth-best-selling album in the United States in 2014.

Pentatonix, together with music producer Ben Bram, won Best Arrangement, Instrumental or A Cappella for "Daft Punk" at the 57th Grammy Awards. Pentatonix also released a documentary on June 18, 2015 called "Pentatonix - On My Way Home", which included clips from their "On My Way Home Tour" in 2015.