Peter Lewis Kingston Wentz III (born June 5, 1979) is an American musician best known as the bassist and lyricist for the rock band Fall Out Boy, since 2001. Before Fall Out Boy, Wentz was a fixture of the Chicago hardcore scene and was the lead singer and songwriter for Arma Angelus, a metalcore band. During Fall Out Boy's hiatus from 2009 to 2012, Wentz formed the experimental, electropop and dubstep group Black Cards. He owns a record label, DCD2 Records, which has signed bands including Panic! at the Disco and Gym Class Heroes.

Fall Out Boy returned from hiatus in February 2013, and have since released three number-one albums; Save Rock and Roll, American Beauty/American Psycho, and Mania.