Mary Star of the Sea is the only studio album by American alternative rock band Zwan, released on January 28, 2003 on Reprise. Produced by frontman Billy Corgan and Bjorn Thorsrud, the album was supported by the singles, "Honestly" and "Lyric".

Zwan was an American alternative rock supergroup formed in 2001 by lead singer and guitarist Billy Corgan and drummer Jimmy Chamberlin, from The Smashing Pumpkins. Other members included bassist Paz Lenchantin of A Perfect Circle, and guitarists David Pajo of Slint, and Matt Sweeney. The band released only one album, Mary Star of the Sea (2003), before breaking up acrimoniously that year during their world tour to promote the album.