With the recognition that improving access to advice and support on sex and relationships is vital in helping young people make positive healthy choices, the present paper explores how young people gain such information and advice. Drawing on the analysis of questionnaire and interview data collected for a local study of 401 young people from Cardiff, aged between 12 and 19 years, the paper discusses the complex and heavily structured picture of young people's sex and relationships information-seeking behaviour. In particular, it explores the varied role(s) that family members, friends and other peers play within this. The paper concludes with a discussion of how these "informal" sources of sex and relationships information and advice in young people's lives may be considered in relation to the development of youth support, sexual health and education policy and practice. (Contains 4 tables and 1 note.)