Internationally, as well as here in the UK, the concept of 'peer pressure' is widely used in analysing the factors influencing young people's experiences of sex and pregnancy - illustrated, for instance, by the following strapline from a recent English government-funded teenage pregnancy national media campaign: 'Should I let my friends control my sex life?' Through a focused interrogation of relevant literature alongside findings from two studies recently conducted by the authors, this paper critically examines some of the complexities of the concept of 'peer pressure', and how it may reveal itself in different contexts. Focusing on young people's narratives of sex and pregnancy, it argues that notions of 'peer pressure' may be inadequate to enable a full appreciation of the range of real pressures that two different groups of young people - those in public care, and a wider cross-section of youth living in the same geographical area - experience. The paper concludes by suggesting that a more sophisticated understanding of how (peer) pressure might operate requires that the concept be contextualised and seen as interacting with other factors influencing young people's experiences of sex and pregnancy. The implications of this analysis in relation to sex and relationships education are discussed.