Income inequality has soared in the United States over the past half century. Has educational inequality increased alongside, in lockstep? Despite the topic's importance, surprisingly little scholarship has focused on long-term changes in the size of the achievement gap between students from higher and lower socioeconomic backgrounds. The authors' new research, presented here, attempts to fill this void, using data from four national assessments of student performance administered to representative samples of U.S. students over nearly five decades. Contrary to recent perceptions, they find the opportunity gap--that is, the relationship between socioeconomic status and achievement--has not grown over the past 50 years. But neither has it closed. Instead, the gap between the haves and have-nots has persisted.