Social and emotional learning (SEL) programs teach disruptive students to improve their classroom behavior. Small-scale programs in high-income countries have been shown to improve treated students' behavior and academic outcomes. Using a randomized experiment, we show that a nationwide SEL program in Chile has no effect on eligible students. We find evidence that very disruptive students may hamper the program's effectiveness. ADHD, a disorder correlated with disruptiveness, is much more prevalent in Chile than in high-income countries, so very disruptive students may be more present in Chile than in the contexts where SEL programs have been shown to work.