Student agency, or the ability to manage one's learning, can have significant effects on academic achievement as students take an active role in seeking and internalizing new knowledge. Students who believe that knowledge can grow over time perform better on IQ tests than students who believe intelligence is invariable (Cury, Elliot, Da Fonseca, & Moller, 2006); students with a growth mindset are more likely to set academic goals focused on mastering content, rather than setting goals focused on achieving a particular test score or course grade (Cury et al., 2006); and students who set mastery-oriented goals tend to process information in a deeper and more organized fashion than those who set performance-oriented goals (Elliot, McGregor, & Gable, 1999). However, less is known about the instructional strategies teachers can use to develop agency in students. To learn more about the practices that support student agency, the American Institutes for Research (AIR) worked with four New Tech Network (NTN) high schools in three states for the study to determine which teacher practices help or hinder the development of student agency, and whether these practices are effective across educational contexts and with different student subgroups. The team at AIR worked alongside fellow scholars, educators, and policymakers to investigate the impact of specific student-centered practices and then translate their findings for cross-sector audiences. This report represents their work over the past two years as they designed, tested, and revised teacher practices as part of a networked improvement community and examined how student agency impacted academic outcomes. [American Institutes for Research (AIR) conducted this study as part of Jobs for the Future's (JFF) Student-Centered Learning Research Collaborative. For the technical appendix, see ED592081.]