The study objective was to analyse the association between food insecurity and the weight and height status of adolescents from a low-income area in the metropolitan region of Rio de Janeiro, Brazil. The population-based cross-sectional survey included 523 adolescents aged 12-18 years, selected by a three-stage cluster sample. Dietary intake was ascertained with a food frequency questionnaire and family food insecurity was assessed with a validated questionnaire. The analysis estimated weighted means of energy and nutrient intakes by families' socioeconomic characteristics and the association between dietary intake with overweight and stunting. The prevalence of mild family food insecurity was 36%, and 24% of the families reported moderate or severe food insecurity. Overweight prevalence was 24%, and the prevalence of stunting was 9%, with no significant differences between sex or age groups. Family food insecurity was associated with unfavourable socioeconomic characteristics, but there was no association between socioeconomic characteristics (including family food insecurity) and overweight or stunting. Moderate or severe family food insecurity was inversely associated with intake of protein and calcium. In addition, stunting was associated with low calcium and iron intake. The co-existence of family food insecurity with overweight and stunting implies a high nutritional risk for adolescents from poor areas of Rio de Janeiro. Nevertheless, the observed absence of a statistical association between family food insecurity and weight status attests to the complexity of this issue.