Objective. To review the literature on the impact of educational asthma interventions in schools regarding the knowledge and morbidity of the disease among children and adolescents. Methods. A systematic review was conducted for controlled clinical trials investigating the effectiveness of educational asthma interventions for students, asthmatic or nonasthmatic, families, and school staff. Databases were CENTRAL, PubMed, LILACS, MEDLINE, and SciELO. Articles published in any language were considered, in the period from 2005 to 2014, according to the PRISMA guidelines. Results. Seventeen articles were selected (N = 5,879 subjects). 94% of the interventions (16 of 17 studies) were applied in developed countries that were led by health professionals and most of them targeted asthmatics. Asthma education promotes the improvement of knowledge about the disease in at least one of the evaluated areas. 29% of the interventions (5 of 17 studies) showed a reduction of the asthma symptoms, 35% (6 of 17 studies) reduction of the hospitalization instances and emergency visits, 29% (5 of 17 studies) reduction of school absenteeism, and 41% (7 of 17 studies) increase in the quality of life of the individuals. Conclusions. Educational interventions in schools raise the awareness of asthma and weaken the impact of morbidity indicators.