Asthma is one of the most common chronic medical conditions in the U.S. It affects 16 million adults and 6.1 million children and results in two million visits to emergency departments, 70,000 hospitalizations, and 5,000 deaths annually. The burden of asthma disproportionately affects persons of lower socioeconomic status. Because asthma can neither be prevented nor cured, current management objectives are to monitor symptoms and objective measures of lung function, to encourage the use of medications that control and prevent symptoms with the fewest adverse effects possible, to control the triggers of asthma symptoms to which a patient is sensitive (such as house dust mites, tobacco smoke, animal dander, and pollens), and to facilitate an asthma care partnership between patients and providers. Effective asthma management has been demonstrated to reduce symptoms, hospitalizations, and urgent care visits. Despite the availability of evidence-based guidelines for the management of pediatric and adult asthma, there remains a significant gap between accepted best practices for asthma care and actual care delivered to asthma patients. The objective of this systematic review was to evaluate the evidence that quality improvement (QI) strategies can improve the processes and outcomes of outpatient care for children and adults with asthma, and to identify the most effective strategies. The two research questions addressed in this study were: Research Question 1: What is the evidence that QI strategies improve the processes and outcomes of outpatient care for pediatric and adult populations with asthma? Specifically, which QI strategies are effective for improving processes and outcomes of asthma care for specific patient populations (e.g., adults, children, low socio-economic status (SES), racial groups, urban/rural)? Also, does the setting of the QI intervention (e.g., home, school, clinic) determine its effectiveness for improving processes and outcomes of asthma care? Research Question 2: Are QI interventions for asthma care that incorporate multiple strategies more effective than those that employ a single strategy?