Research has shown that parents tend to pass educational advantage or disadvantage on to their children. However, little is known about the extent to which the intergenerational transmission of education involves children's agency. In this study we drew from two traditions in sociological and social psychological theorizing--the theory of cultural and social reproduction and the theory of human agency--to examine whether agency influences children's educational performance, and if so, whether this influence can be observed among children across social classes. We used data from the Spanish sample of the Program for International Student Assessment (N = 25,003 15-year-olds). Results indicate that the level of child agency was weakly positively related to social class, that child agency impacted on a child's educational performance, and that the positive effect of agency on educational performance did not vary by social class. This suggests that strategies to enhance disadvantaged children's agency may prove useful in reducing social gradients in educational performance. More generally, our findings may ignite a debate about the role that social structure and human agency play in shaping social inequality and mobility.