Susan Cowsill is an American musician. She joined The Cowsills in 1967 and later released two singles for Warner Brothers by 1977. In the '80s, she became a full-time member of Dwight Twilley's band, contributing vocals to several of his albums. She released her own album Just Believe It featuring Adam Duritz and Lucinda Williams, which includes her most popular song of the same name. Cowsill then joined the alt-country supergroup the Continental Drifters from 1994 to 2001 and released the album Lighthouse. She has also collaborated with Johnny Sansone on the song Who Knows Where the Time Goes and Lucinda Williams on Nanny's Song. Susan Cowsill appears in the documentary Family Band: The Cowsills Story.