Adolescence, with its change in dietary habits, is likely to be a vulnerable period in the onset of obesity. It is considered that peers have an important role to play on adolescents' diet, however, limited research has examined the role of peers in this context. This study examined the relationship between self-efficacy for healthy eating, parent and peer support for healthy and unhealthy eating and food intake patterns. Participants were 264 boys and 219 girls (N = 483), aged 13-18 years, recruited from post-primary schools in Ireland. Self-report measures assessed self-efficacy, parent and peer support for healthy eating, and for unhealthy eating. Dietary pattern analysis, a popular alternative to traditional methods used in nutritional research, was conducted on a FFQ to derive food intake patterns. Two patterns were identified labelled 'healthy food intake' and 'unhealthy food intake'. Multi-group modelling was used to evaluate whether the hypothesized model of factors related to dietary patterns differed by gender. The multi-group model fit the data well, with only one path shown to differ by gender. Lower self-efficacy for healthy eating and higher peer support for unhealthy eating were associated with 'unhealthy food intake'. Higher self-efficacy was associated with 'healthy food intake'. Prevention programs that target self-efficacy for eating and peer support for unhealthy eating may be beneficial in improving dietary choices among adolescents. (C) 2012 Elsevier Ltd. All rights reserved.