ABSTRACTThe link between participation in school-sponsored sports and academic performance has been studied extensively in the literature. Whilst previous studies tend to show positive academic spillovers, it remains unclear whether these positive associations are primarily driven by selection into sports. We investigate this issue using data on middle school children drawn from the Early Childhood Longitudinal Study, Kindergarten Class of 1998–1999. Due to the lack of credible instrumental variables for sports participation, we establish bounds for the relationship between school sports and academics using a combination of the propensity score matching method and an approach that uses selection on observed factors as a guide to selection on unobserved factors. We find that the association between participation in school-sponsored sports and academic performance as measured by standardised test scores in reading, math and science ranges from null to negative. Overall, our results suggest that failure to account for selection may result in a misleading positive correlation between sports participation and academic performance.