China’s rapid development and urbanization has induced large numbers of rural residents to migrate from their homes in the countryside to urban areas in search of higher wages. As a consequence, it is estimated that more than 60 million children in rural China are left behind and live with relatives, typically their paternal grandparents. These children are called Left Behind Children (or LBCs). There are concerns about the potential negative effects of parental migration on the academic performance of the LBCs that could be due to the absence of parental care. However, it might also be that when a child’s parents work in the city away from home, their remittances can increase the household’s income and provide more resources and that this can lead to better academic performance. Hence, the net impact of out-migration on the academic performance of LBCs is unclear. This paper examines changes in academic performance before and after the parents of students out-migrate. We draw on a panel dataset collected by the authors of more than 13,000 students at 130 rural primary schools in ethnic minority areas of rural China. Using difference-in-difference and propensity score matching approaches, our results indicate that generally parental migration has significant, positive impacts on the academic performance of LBCs (which we measure using standardized English test scores). Heterogeneous analysis using our data demonstrates that the positive impact on LBCs is greater for poorer performing students.