Pentatonix (often abbreviated as PTX) is an American a cappella group of five vocalists originating from Arlington, Texas. The group won the third season of The Sing-Off on NBC in 2011, singing an a cappella arrangement of "Eye of the Tiger", which was originally performed by the band Survivor, as their victory song. Pentatonix won $200,000 and a recording contract with Sony. Their debut EP, PTX, Volume 1 (2012), charted at number 14 on the Billboard 200 and their second release, PTX, Vol. II (2013), debuted number 10 on the Billboard 200 and number 1 for Independent Albums. They have sold over 500,000 records. The group's third album PTX, Vol. III was released on September 23, 2014, which will be followed by a Christmas album on October 23.

The group will join the cast of the a cappella-centric film Pitch Perfect 2, slated for release May 15, 2015.