The notion of "student voice," or a student role in the decision making and change efforts of schools, has emerged in the new millennium as a potential strategy for improving the success of school reform efforts. Yet few studies have examined this construct either theoretically or empirically. Grounded in a sociocultural perspective, this article provides some of the first empirical data on youth participation in student voice efforts by identifying how student voice opportunities appear to contribute to "youth development" outcomes in young people. The article finds that student voice activities can create meaningful experiences for youth that help to meet fundamental developmental needs -- especially for students who otherwise do not find meaning in their school experiences. Specifically, this research finds a marked consistency in the growth of agency, belonging and competence --three assets that are central to youth development. While these outcomes were consistent across the students in this study, the data demonstrate how the structure of student voice efforts and nature of adult/student relations fundamentally influence the forms of youth development outcomes that emerge.