This paper examines the associations between food insecurity, participation in the National School Lunch Program (NSLP), and children's well-being. We address problems of selection by restricting our sample to children in families in which at least one child participates in the NSLP. Results suggest that food insecurity is associated with behavioral problems, but not health or cognitive difficulties, among children. Additionally, after adjusting for selection, participation in the NSLP does not significantly impact child outcomes; the exception is for children in families experiencing child hunger, for whom participation is associated with reduced behavioral problems.