Charter schools have been on the educational reform landscape for over twenty years. In the last ten years, a number of rigorous studies have examined the effects of these schools on student achievement and educational attainment. Findings reveal mixed results where student achievement is concerned (i.e., some positive, some negative, some neutral) and positive results in terms of educational attainment (i.e., high school graduation and college attendance). The article places this research within a framework that draws on both market and institutional theories, and concludes that additional research on the social organization of charter schools and traditional public schools is needed to better understand the conditions under which school choice is or is not effective.Expected final online publication date for the Annual Review of Sociology Volume 41 is July 30, 2015. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.