This manual promotes the acquisition of factual information, the formation of positive attitudes, beliefs and values, as well as the development of skills to cope with the biological, psychological, socio-cultural and spiritual aspects of human sexuality. The overall goal of the manual is to create a positive and comprehensive educational programme that helps students gain knowledge, values and skills to lead sexually healthy and responsible lives. The manual is designed to help adolescents to: develop self-acceptance through self-awareness; respect themselves as sexual persons (including their bodies, feelings, attractions); appreciate differences among individuals; increase comfort and skills in discussing sexuality issues with peers and adults; explore and develop values, attitudes and feelings about their own sexuality; increase knowledge and skills for avoiding unplanned pregnancy and STIs, including preventing HIV; acquire skills to assist in making positive decisions for themselves; acquire information and skills for taking care of their sexual health; develop knowledge and skills that will help them maintain caring, supportive, non-coercive and mutually pleasurable relationships (sexual and non-sexual). The purpose of this document is to assist parents, teachers, adults and youth programme implementers in helping adolescents go through one of the most demanding times of their lives. The manual has been developed for young people in Nigeria. The document provides instructional materials for teaching topics under the six key concepts identified in the "Guidelines for Comprehensive Sexuality Education in Nigeria" (human development, relationships, personal skills, sexual behaviour, sexual health, and society and culture). Each concept covers several topics, and each topic covers several lessons that will help teachers facilitate learning of the topic. It is divided into three parts: Trainers' guide (which contains an introduction, adolescent needs and development, guidance notes on the manual, and implementation suggestions); outline of the study/instructional materials (which includes the modules developing the six key concepts); Resource materials. This comprehensive manual proposes a step-by-step approach to the teaching of sexuality education. It aims to provide a response to HIV and AIDS, as well as promoting positive sexuality. It combines prevention and skills development messages with messages that support the development of a positive sense of self, healthy sexuality and healthy relationships for young people in Nigeria.