"Lonely Days" is a ballad written and performed by the Bee Gees. It appeared on their album 2 Years On, and was released as a single, becoming their first Top Five hit in the US, peaking at number three in the Billboard Hot 100 and reaching number one in the Cashbox and Record World charts. Barry Gibb later re-recorded the song with country quartet Little Big Town for his 2021 album Greenfields.