There is widespread concern that the rising costs of higher education are making college unaffordable for many students and their families. Federal and state support is central to promoting college affordability; however, persistent state budget constraints have limited funding for public colleges. GAO was asked to study state policies affecting affordability and identify approaches to encourage states to make college more affordable. This report examines, among other things, how state financial support and tuition have changed at public colleges over the past decade. It also examines how the federal government works with states to improve college affordability and what additional approaches are available for doing so. In conducting this work, GAO analyzed trends in state funding for public colleges, tuition, and state student aid using data from the U.S. Department of Education for all public sector colleges from fiscal years 2003 through 2012, the most recent data available at the time of this study. GAO also identified academic studies on state higher education policies and affordability published since 2011 and interviewed 25 academic experts and organizations in the fields of higher education or state policy. Finally, GAO reviewed Education programs and proposals and obtained perspectives from experts and organizations to identify approaches the federal government could use to incentivize state action. GAO does not make recommendations in this report. The following are appended: (1) Objectives, Scope, and Methodology; (2) Trends in State Grant Aid to Students and Sources of Revenue for Public Colleges; (3) Bibliography; (4) Related GAO Products; and (5) GAO Contacts and Staff Acknowledgments. [In addition to the GAO contact, Melissa Emrey-Arras, Meeta Engle (Assistant Director), Charline Gay, Amy Moran Lowe, Jean McSween, John Mingus, Katherine Morris, Amrita Sen, and Jack Wang made significant contributions to this report. Also contributing to this report were James Bennett, Deborah Bland, Jessica Botsford, David Chrisinger, Peter del Toro, Ashley McCall, Sheila McCoy, Susan Offutt, Michelle Sager, Stephen Sanford, Anjali Tekchandani, and Greg Whitney.]