Peter Lewis Kingston Wentz III (born June 5, 1979) is an American musician who serves as the bassist and lyricist for the rock band Fall Out Boy since its formation in 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 four albums; Save Rock and Roll, American Beauty/American Psycho, Mania, and So Much (for) Stardust.Wentz has also ventured into other non-musical projects, including writing, acting, and fashion; in 2005 he founded a clothing company called Clandestine Industries. He hosts the TV show Best Ink and runs a film production company called Bartskull Films, as well as a bar called Angels & Kings. His philanthropic activities include collaborations with Invisible Children, Inc. and UNICEF's Tap Project, a fundraising project that helps bring clean drinking water to people worldwide, People magazine states that "no bassist has upstaged a frontman as well as Pete Wentz of Fall Out Boy." He is also a minority owner of the Phoenix Rising FC, a USL Championship team.