A higher proportion of adolescents from families in a lower socioeconomic position (SEP) tends to have more unhealthy dietary behaviours, and overweight and obesity, than their counterparts in higher SEPs. More research is needed to understand the causes of these differences, in particular the influence of the neighbourhood environment, which has been explored less. The presented qualitative study explores how adolescents and their parents from higher and lower SEP neighbourhoods perceive the social and physical environment influencing adolescents’ dietary behaviours. We conducted 6 semi-structured focus groups with 35 13–14 year olds and 8 interviews with some of their parents. The interviewees were recruited from one higher and two lower SEP neighbourhoods in Oslo, Norway. Theme-based inductive coding was used for analysis, and the results discussed in light of an ecological framework. The results indicate that all the adolescents experience several barriers to healthy dietary behaviours. For adolescents in the lower SEP neighbourhood, one or both parents desired their cultural cuisine served at home, whereas the adolescents wanted and often consumed western dishes. Fast-food restaurants or hanging out at the mall was perceived as the preferred social arena, often due to lack of involvement in either leisure-time physical activities or youth clubs as a safe, engaging option. The adolescents in the higher SEP neighbourhood perceived social norms which accentuated healthy dietary choices. When more possibilities for activities were present and the adolescents expressed being highly engaged in leisure-time physical activity, this also seemed to facilitate healthier dietary behaviours. These findings indicate how several factors simultaneously can influence dietary behaviour. Use of a multi-layered approach when exploring the environmental influences could increase knowledge about tackling social inequalities in dietary behaviours among adolescents.