"Have You Never Been Mellow" is a popular song written by John Farrar and recorded by Olivia Newton-John as the title track for her album of the same name.

In March 1975, the single became Newton-John's second consecutive number one hit on the U.S. Billboard Hot 100, although it stayed in the top chart position for just one week. The record also received a Grammy nomination for Best Female Pop Vocal Performance. The song also topped the Billboard Hot Adult Contemporary Singles chart and — in her continued success as a crossover artist — peaked at No. 3 on the Hot Country Singles chart.

In the United States, it was Newton-John's fourth straight single to be certified gold for sales of one million copies. "Have You Never Been Mellow" also reached number one in Canada and peaked at number 10 in Australia and number 26 in Japan, but was not much of a success elsewhere in the world, failing to chart altogether in the United Kingdom.

The song is being performed as part of the 2007 Broadway musical Xanadu.

Along with her later single Xanadu, a remixed version by "The Olivia Project" appears in the Dance Dance Revolution series of video games.

The Dutch band Party Animals sampled the song in 1996 on their hit "Have You Ever Been Mellow". The song reached number one on the Netherlands singles chart.

The punk band the Feederz covered the song on their 1984 debut album "Ever Feel Like Killing Your Boss?".