List of The Guess Who members

The Guess Who was a Canadian rock band, originating as The Guess Who? in 1966, and adopting the name The Guess Who in 1968. They were most successful from 1969 to 1975, under the leadership of singer/keyboardist Burton Cummings. During that period they released eleven studio albums, all of which reached the charts in Canada and the United States; their 1970 album American Woman reached no. 1 in Canada and no. 9 in the United States, and five other albums reached the top ten in Canada. They also achieved five number one singles in Canada and two in the United States.

During the 1969-1975 era prior to the band's breakup, Cummings and drummer Garry Peterson were the only consistent members; they were joined by five guitarists and two bassists during those years. Cummings ended the band in 1975 and embarked on a solo career. In the following decades, Cummings and original guitarist Randy Bachman led several one-time reunion shows or short commemorative tours with various former members.

Starting in the late 1970s, original bassist Jim Kale organized a band under the name of The Guess Who for nostalgia tours with a frequently changing cast of musicians. Kale departed temporarily on some occasions and the surviving band often performed with no original members. Peterson appeared in both Kale's band and the reunion tours with Cummings and Bachman. Kale retired in 2016, and Peterson (the final remaining original member) continues to lead a band using the name The Guess Who without any other original members, and this band occasionally releases albums of new music.

This list article does not include musicians who filled in temporarily for official members.