This Information Brief was developed by WHO's Department of Child and Adolescent Health and Development to support staff of the Organization and other UN agencies working at global, regional and national levels in promoting the uptake of effective interventions to improve the sexual and reproductive health of adolescents through schools in low-income countries. The premise of the Brief is that school-based sexual and reproductive health education is one of the most important and widespread ways to help adolescents to recognize and avert risks and improve their reproductive health. This evidence-based information brief establishes ways in which the health sector can help the education sector provide appropriate information to adolescents about when and why they need to use health services and where these may be available. This information is helpful to generate demand and create support for the provision and use of health services by adolescents. The health sector needs to be in a position to ensure that the information that is provided through schools is technically sound and is consistent with other messages that adolescents are receiving about sexual and reproductive health including HIV, and that the strategies that are being implemented are evidence based. The health sector's collective expertise and strong credibility make it a valuable ally for mobilizing partners, dispelling misperceptions, providing evidence-based arguments and encouraging the development of sound policies and practices for the promotion of sexual and reproductive health in schools.