"Welcome Back" is a popular record that was the theme song of the 1970s American television sitcom Welcome Back, Kotter. Written and recorded by former Lovin' Spoonful frontman John Sebastian, it reached No. 1 on the Billboard Hot 100 chart for one week in May 1976 after only five weeks on the chart, and also topped the adult contemporary chart. It also reached No. 93 on the country chart.

John Benson Sebastian (born March 17, 1944) is an American singer, songwriter and musician who founded the rock band the Lovin' Spoonful. He made an impromptu appearance at the Woodstock festival in 1969 and scored a U.S. No. 1 hit in 1976 with "Welcome Back."