John Peter Farnham AO (born 1 July 1949, Dagenham, Essex, England), (formerly billed as Johnny Farnham from his professional debut 1967 until 1980), is an English-born Australian pop singer. Farnham was a teen pop idol from 1964 to 1979, and has since forged a career as an adult contemporary singer. His career has mostly been as a solo artist although he temporarily replaced Glenn Shorrock as lead singer of Little River Band during 1982–1985. In September 1986 his solo single, "You're the Voice" peaked at No. 1 on the Australian singles charts. The associated album, Whispering Jack, held the No. 1 position for a total of 25 weeks, and is the highest-selling album in Australian history. Both the single and the album had Top Ten success internationally including No. 1 in Sweden.

Domestically he has remained one of Australia's best-known performers with a career spanning over 45 years, and he is the only Australian artist to have a number one record in five consecutive decades (echoeing that of Cliff Richard in the UK) with singles: "Sadie (The Cleaning Lady)" in 1967, "Raindrops Keep Fallin' on My Head" in 1969/1970, and "Age of Reason" in 1988; and albums: Age of Reason, Chain Reaction in 1990, Then Again... in 1993, Anthology 1: Greatest Hits 1986–1997 in 1997, 33⅓ in 2000 and The Last Time in 2002.