Parental psychiatric morbidity related to experiences of war and trauma has been associated with adverse psychological outcomes for children. The aim of this study was to investigate parental post-traumatic stress in relation to psychiatric care utilization among children of refugees with particular attention on the child's own refugee status, sex of both child and parents, and specific psychiatric diagnoses. This was a register study in a population of 16 143 adolescents from refugee families in Stockholm County born 1995-2000 and followed between 2011 and 2017 (11-18 years old). Parental post-traumatic stress, identified in three levels of care, was analysed in relation to child and adolescent psychiatric care use. Cox regression analysis was used to estimate hazard ratios (HR) and 95% confidence intervals (CI), adjusted for duration of residence and demographic and socioeconomic variables. Having a mother with post-traumatic stress was associated with higher psychiatric care utilization, with adjusted HR 2.44 (95% CI 1.90-3.14) among foreign-born refugee children and HR 1.77 (1.33-2.36) among Swedish-born children with refugee parents, with particularly high risks for children with less than five years of residence (HR 4.03; 2.29-7.10) and for diagnoses of anxiety and depression (HR 2.71; 2.11-3.48). Having a father with post-traumatic stress was not associated with increased HRs of psychiatric care utilization. Similar results were seen for boys and girls. Treatment for post-traumatic stress should be made available in refugee reception programmes. These programmes should use a family approach that targets both parents and children.