<p>Children in economically marginalized communities who experience food insecurity are at greater risk of disruptive behaviors in schools. Preventive interventions that address hunger and antecedent triggers in the classroom may benefit this student group. Using a concurrent multiple baseline design, this study examined the relationship between a classroom intervention that combined Second Chance Breakfast and mindfulness and the classroom behaviors of urban elementary school students in three classrooms. Visual analysis indicated that classrooms offering Second Chance Breakfast and mindfulness had a modest increase in academically-engaged behaviors. Quantitative analysis provided statistically significant evidence of intervention effects on academically-engaged behaviors for two out of the three classrooms. The intervention package was judged to be socially valid among the teachers and students. The results of the current study provide further evidence on the effectiveness of prevention-based, universal interventions in promoting student wellbeing and improving classroom behaviors, especially in schools with students from racially, ethnically, and economically marginalized backgrounds.</p>