John Peter Farnham, Jr. AO (born 1 July 1949) is an Australian pop rock singer. Farnham was a teen pop idol from 1967 to 1979, billed then as Johnny Farnham, but has since forged a career as an adult contemporary singer. His career has mostly been as a solo artist although he replaced Glenn Shorrock as lead singer of Little River Band from 1982 to 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 2nd 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 and most popular performers with a career spanning 50 years, and he is the only Australian artist to have a number one record in five consecutive decades (echoing that of Sir Cliff Richard in the UK) with singles: Sadie (The Cleaning Lady) in 1967, Raindrops Keep Fallin' on My Head in 1970, and Age of Reason in 1988; and albums: Whispering Jack in 1986, Age of Reason in 1988 Chain Reaction in 1990, Then Again... in 1993, 33⅓ in 2000, and The Last Time in 2002, as well as collaborative albums with Olivia Newton John, including Highlights from The Main Event in 1998, (also with Anthony Warlow), Two Strong Hearts Live in 2015 and Friends for Christmas in 2016.

Farnham has been recognised by honours and awards including 1987 Australian of the Year, 1996 Officer of the Order of Australia, and 19 ARIA Awards including his 2003 induction into the Hall of Fame. From 1969 he was voted by TV Week readers as the 'King of Pop' for five consecutive years. Aside from his recording career, Farnham performed on stage with lead roles in Australian productions of Charlie Girl, Pippin and 1992's Jesus Christ Superstar. He starred in his own TV series and specials including It's Magic (With Colleen Hewett), Bobby Dazzler and Farnham and Byrne (with Debra Byrne) and as a guest on numerous other popular shows such as The Don Lane Show, Countdown and Hey Hey It's Saturday. Australian rock historian, Ian McFarlane described him as "the most successful solo artist in the history of Australian rock and pop ... Farnham has retained an affable sense of humour and a simple, unpretentious 'everyman' charm which also makes him one of the most respected celebrities in Australian entertainment history."