The Learning Initiative on Norms, Exploitation and Abuse (LINEA) is a cluster randomised controlled trial (CRCT) of an intervention (radio drama and curricula) which aims to prevent age-disparate transactional sex in Tanzania. This dataset contains the responses to structured surveys conducted at baseline before randomisation to and implementation of the LINEA intervention, among a cohort of adolescent girls aged 13-15 years and a cohort of young men aged 23-50 years. The surveys covered topics including socio-demographics, schooling, sexual behaviour, receipt and giving of gifts in the context of sex, experience of violence, attitudes to violence, and attitudes to age-disparate transactional sex.