Sexual minorities' risk for exclusionary discipline is a commonly cited indicator of the challenges that these students face. The current study addresses this issue by introducing a new data source for research on sexual minority students: the Fragile Families and Childhood Wellbeing Study. In this geographically diverse, population-based sample, I find that sexual minorities continue to face higher rates of discipline than their peers. However, this risk is highly stratified by sex: Same-sex attraction is associated with 95% higher odds of discipline among girls but no apparent discipline risk among boys. Sexual minority girls' risk for discipline is only partially mediated by behavior, a result that is plausibly consistent with the interpretation that these students continue to face discriminatory treatment in schools.