Massachusetts faces challenges in preparing all students for lifelong success, with substantial disparities in both opportunities and outcomes. For instance, on the 2017 National Assessment of Educational Progress, less than 30 percent of black and Latino fourth graders in Massachusetts demonstrated proficiency in reading, compared to 60 percent of their white peers. The disparity is equally stark in eighth grade math, with only 22 percent of black and 29 percent of Latino students achieving proficiency, versus 56 percent of white students. Meanwhile, low-income students have significantly fewer opportunities than their peers to take part in the types of applied learning experiences that extend and deepen what they learn in school. In 2006, national data indicated that the wealthiest parents spent more than 6.7 times as much as parents in the lowest income quintile on enrichment activities for their children. Even when school systems offer robust in-school and out-of-school enrichment programs, few are set up to address this wide of a gap. The persistence of these disparities in outcomes and opportunities points to the need to look deeply into the root causes of ineffectiveness and inequity. It is impossible to fully understand the challenges of the educational system if we're not hearing from those most affected by it. This report explores how focusing on student voice, along with the closely linked concepts of student agency and leadership, can serve as a necessary lever for equity and effectiveness. It starts by laying out what it means by student voice, why it matters, and what it looks like in action. [For the executive summary, see ED594109.]