Tom Marshall (born November 12, 1963) is an American lyricist, keyboardist and singer-songwriter best known for his association with Trey Anastasio and the rock band Phish. He has been the primary external lyricist for Phish during their career (1983–2004, 2009–present), with songwriting credits for more than 95 originals. In addition to his songwriting work, Marshall also fronts the rock band Amfibian and hosts the Phish podcast Under the Scales. Marshall is the co-founder of Osiris, a podcast network in partnership with Jambase.