This article proposes a critical look at the non-formal education strategies, which have been conducted mainly in Dar es Salaam, Tanzania, by four nongovernmental organizations, in order to provide sexual education to girls between the ages of 12 and 16, showing the role played by the civil society in contradicting the school conservatism. Clear trends emerged from this study to indicate that sexual risky behaviours, unintended pregnancies, and HIV transmission among adolescent girls are closely related to intentional as well as unintentional reproduction of the power relations, social meanings, moral codes, stigma and silence attached to adolescents, their sexuality and sexual health within key institutions. As a result, their sexual behaviours are hidden and ignored. As schools do not develop curricula for life, NGOs play their role by means of non-formal education.