Objectives Young people's perspectives on the association between having a family member with a chronic health concern (FHC) and their own health are under-researched. This study used young people's reports to assess the prevalence of FHCs and their association with negative health outcomes, with an aim of identifying potential inequalities between marginalised and non-marginalised young people. Family cohesion was examined as a moderating factor. Design Cross-sectional data from the Australian Child Wellbeing Project survey were used. Respondents were asked whether someone in their family experienced one or more FHCs (disability, mental illness or drug/alcohol addiction). In addition, their experience of different psychosomatic symptoms (headache, sleeplessness, irritability, etc), aspects of family relationships and social and economic characteristics (disability, materially disadvantaged and Indigenous) were documented. Setting Nationally representative Australian sample. Participants 1531 students in school years 4 and 6 and 3846 students in year 8. Results A quarter of students reported having an FHC (years 4 and 6: 23.96% (95% CI 19.30% to 28.62%); year 8: 25.35% (95% CI 22.77% to 27.94%)). Significantly, more students with FHCs than those without reported experiencing 2 or more negative health symptoms at least weekly (OR=1.78; 95% CI 1.19 to 2.65; p<0.01). However, an independent relationship between FHCs and symptom load was only found in the case of FHC-drug/alcohol addiction. Marginalised students and students reporting low family cohesion had an increased prevalence of FHCs and notably higher symptom loads where FHCs were present. Level of family cohesion did not impact the relationship between FHCs and symptom load. Conclusions The burden of FHCs is inequitably distributed between marginalised and non-marginalised groups, and between young people experiencing different levels of family cohesion. More work is required regarding appropriate targets for community and family-level interventions to support young people in the context of FHCs.