Purpose: The purpose of the paper is to investigate how young people are using school-based sources of sex and relationships education (SRE) to obtain information and advice. Design/methodology/approach: The paper shows how anonymous self-completion questionnaires were administered to young people aged between 12 and 19 years in three secondary school and six out-of-school youth settings (n=401). Follow-up focus group interviews were conducted with 12 groups of young people from the school and out-of-school settings (n=57). Findings: The paper finds that school lessons were the most frequent source of sex and relationships information for many young people. Lessons were reported to be most useful for students who were male, younger and more educationally engaged. School lessons were widely criticised by young people as predominantly focusing on biological aspects of sex and relationships and lacking a discursive or participatory element. Young people perceived a diminishing commitment to SRE by teachers as they progressed into later years. Research limitations/implications: The paper examines a predominantly working-class sample of young people from one urban area of South Wales. Practical implications/implications: On the basis of the data analysis in this paper a number of suggestions are made regarding the nature of future school provision of SRE. Originality/value: This paper raises awareness and highlights issues surrounding the role of schools, teachers and school nurses in sex and relationships education. (Contains 3 tables and 1 figure.)