Ten million children in the United States have asthma. Since children are in school about 6 hr a day, school nurses are positioned to intervene and influence asthma outcomes. A descriptive correlational study was designed to investigate performance of school nurses' asthma management behaviors in relationship to asthma knowledge, asthma attitude, asthma self-efficacy, and rating of importance of asthma management behaviors. Results indicated that asthma attitude, asthma self-efficacy, and rating of importance of asthma management behaviors were associated with performance of asthma management behaviors. The higher the rating of importance of asthma management behaviors, the more likely school nurses were to perform the behaviors (p < 0.05). Higher levels of asthma self-efficacy were associated with performance of asthma management behaviors, indicating the importance of strengthening school nurses' asthma self-efficacy in asthma management. By understanding factors influencing performance of asthma management behaviors by school nurses, interventions can be implemented to increase asthma management behaviors, leading to improved outcomes for students with asthma.