Asthma rates are increasing in children. School nurses have opportunities to care for children with asthma but need to overcome barriers impacting their ability to manage asthma in the school setting. This study (a) assessed barriers present in the school setting, (b) determined the impact of barriers on performance of asthma management behaviors, and (c) determined the impact of barriers on importance ratings of asthma management behaviors, asthma self-efficacy, and asthma attitudes (N = 537). Results revealed 72% of the nurses reported at least one barrier. As numbers of barriers increased, performance of asthma management behaviors decreased. Significant relationships were found between specific asthma management behaviors and specific barriers. No significant relationships were found between barriers and asthma self-efficacy, asthma attitude, or importance ratings of asthma management behaviors. Removing barriers may allow the nurse to perform at greatest effectiveness, enhancing the positive outcomes that result from appropriate asthma management.