Health education, as defined by the World Health Organization (WHO 1983), includes sex education. In Tunisia, there is a growing interest in sexuality issues, in contrast with the reigning conservative culture, challenging the taboos and restrictions imposed by religion. A global sex education strategy is therefore required in Tunisian in schools to help students understand their body and its biological functions, construct a real sexual identity and adopt behaviours that promote a healthy and low-risk lifestyle. In this study, we wonder whether the objectives defined by official programmes and conveyed by biology teachers are consistent with the expectations of their students in terms of sex education. This questionnaire-based survey, conducted among 95 biology teachers and 735 students, with an average age of 18 years, shows to what extent the objectives of biology teachers differ from the expectations of students, illustrating to what extent sex education needs to be adapted.