Has the achievement of U.S. students improved over the past half century? Have gaps between racial, ethnic, and socioeconomic groups widened or narrowed? These and similar questions provoke near-constant conversation. But answers are uncertain, partly because research to date has yielded inconsistent findings. In this article, the authors bring together information from every nationally representative testing program consistently administered in the United States over the past 50 years to document trends in student achievement from 1971 to 2017, the last year for which detailed information is currently available.