Background: Childhood asthma is a serious and common chronic disease that requires the attention of nurses and other school personnel. Schools are often the first setting that children take the lead in managing their asthma. Often, children are ill prepared for this role. Our study evaluated a school-based, multifaceted asthma program that targeted students with asthma and the broader school community. Methods: A randomized trial involving 130 schools with grades 1-5 and 1316 children with asthma and their families was conducted. Outcomes of interest for the child, at 1?year, were urgent care use and school absenteeism for asthma, inhaler technique, and quality of life, and for the school, at 14?months, were indicators of a supportive school environment. Results: Improvements were observed at the child and school level for the intervention group. Fewer children in the intervention group had a school absence (50% vs 60%; p?<?0.01), required urgent care for asthma (41% vs 51%; p?<?0.0001), or reported a day of interrupted activity (51% vs 63%; p?<0?.01), and had improved quality of life (5.8?±?1.2 vs 5.4?±?1.4; p?<?0.0001). Schools in the intervention group were more likely to have practices supporting an asthma-friendly environment. Conclusions: Implementation of a multifaceted school-based asthma program can lead to asthma-friendly schools that support children with asthma to be successful managers of their asthma and experience improved quality of life and decreased disease associated burden.