The purpose of this review was to synthesize the literature on attrition and retention in instrumental music and to identify strategies to encourage students' continued participation in school bands and orchestras. Retaining members from 1 year to the next is a key factor in building ensembles and helping individual musicians reach their full potential. At least 35 years of research, however, has yielded little consistency in determining why students persist in or dropout of instrumental study. Most decisions likely involve (a) practical considerations, especially related to scheduling and other interests and commitments; (b) students' attitudes on their musicianship and various aspects of the program; and (c) the influence of other people. The MUSICSM Model of Motivation can provide a framework through which stakeholders examine how their school bands and orchestras meet the needs of students, thus influencing their decisions to leave or remain in the program.