Thomas O'Malley

• Thomas Francis O'Malley, American politician
• Thomas O'Malley (congressman), U.S. representative from Wisconsin
• Thomas J. O'Malley, American politician, lieutenant governor of Wisconsin
• Thomas O'Malley (writer), Irish writer
• Thomas P. O'Malley, American Jesuit and academic
• Thomas D. O'Malley Jr., American politician, treasurer of Florida
• Tom O'Malley, former American Major League Baseball player
• Tom O'Malley (American football), American football player
• T. J. O'Malley, American aerospace engineer
• Thomas O'Malley, British bassist, bassist for Ingested, Worm Shepherd and Steel Mage
• Thomas O'Malley, the alley cat in the film ''The Aristocats''