This teachers' guide is part of the official Family Life and HIV Education (FLHE) curriculum in Nigeria. It includes sexual health topics from a scientific perspective. The main objective of the guide is to help learners to: (i) develop a positive and factual view of themselves; (ii) acquire the information and skills they need to take care of their health, including preventing HIV; (iii) respect and value themselves and others, and (iv) acquire the skills needed to make healthy decisions about their sexual health and behaviour. The guide is designed to give guidance to school teachers, and allow flexibility to suit the specificities of different Nigerian communities. It is expected that teachers will make use of this document to achieve the goals of FLHE education in Nigeria. The document is divided into three levels: Lower Basic, which discusses three FLHE topics: communication, the human body and HIV transmission; Middle Basic, which discusses four FLHE topics: HIV and AIDS, abuse, body image and puberty; Upper Basic, which discusses five FLHE topics: relationships, puberty, decision-making, values and body image. The curriculum prescriptions presented in this teacher's guide represent the minimum content of FLHE to be taught within the appropriate topic(s) of the basic science curriculum. If adequately implemented, learners will receive education that fosters the acquisition of factual information, the formation of positive attitudes and values, as well as the skills to prevent infection and the spread of HIV and AIDS. It will also help develop skills to cope with the biological, psychological, socio-cultural and spiritual aspects of human life.