This is the third collection of papers in Optimality Theory to be published in the University of Massachusetts Occasional Papers (UMOP) series. Many of these papers were presented at HUMDRUM 2005, held in April of that year at the University of Massachusetts, Amherst. This volume includes papers by Michael Becker, Joan Chen-Main, Sara Finley, Kathryn Flack, Christa Gordon, Nancy Hall, Shigeto Kawahara, Michael Key, Seunghun Julio Lee, John J. McCarthy, Michael O'Keefe, Joe Pater, Ehren M. Reilly, and Matthew Wolf.