Peter Paul Cetera ( sə-TERR-ə; born September 13, 1944) is a retired American musician best known for being a lead vocalist and the bassist of the rock band Chicago from 1967 until his departure in 1985, before launching a successful solo career. His career as a recording artist encompasses 17 albums with Chicago and eight solo albums.

With "If You Leave Me Now", a song written and sung by Cetera on the group's tenth album, Chicago garnered its first Grammy Award. It was also the group's first number one single.

As a solo artist, Cetera has scored six Top 40 singles, including two that reached number one on Billboard's Hot 100 chart in 1986, "Glory of Love" and "The Next Time I Fall". "Glory of Love", the theme song from the film The Karate Kid Part II (1986), was co-written by Cetera, David Foster, and Diane Nini, and was nominated for both an Academy Award and a Golden Globe Award for best original song from a motion picture. In 1987, Cetera received an ASCAP award for "Glory of Love" in the category "Most Performed Songs from Motion Pictures". His performance on "Glory of Love" was nominated for a Grammy Award for best pop male vocal. That same year Cetera and Amy Grant, who performed as a duet on "The Next Time I Fall", were nominated for a Grammy Award for best vocal performance by a pop duo or group.

Besides David Foster and Amy Grant, Cetera has collaborated throughout his career with other nationally and internationally known recording artists from various genres of music. His songs have been featured in soundtracks for movies and television.

In 2014, Chicago's first album, Chicago Transit Authority (Columbia, 1969), featuring Cetera on bass and vocals, was inducted into the Grammy Hall of Fame. Cetera was inducted into the Rock and Roll Hall of Fame as a member of Chicago in April 2016, and he, Robert Lamm, and James Pankow were among the 2017 Songwriters Hall of Fame inductees for their songwriting efforts as members of the group. Cetera, along with other members of Chicago, received a Grammy Lifetime Achievement Award in 2020.