The author examined the relationship between student engagement and academic performance, using U.S. data of the Program for International Student Assessment 2000. The sample comprised 3,268 fifteen-year-old students from 121 U.S. schools. Multilevel analysis showed that behavioral engagement (defined as effort and perseverance in learning) and emotional engagement (defined as sense of belonging) significantly predicted reading performance. The effect of emotional engagement on reading performance was partially mediated through behavioral engagement. Findings from the present study suggest that educators, policy makers, and the research community need to pay more attention to student engagement and ways to enhance it.