The purpose of this study is to examine the association between poverty and child mental disorders, and in particular, address an important knowledge gap by examining the influence of primary carer mental health in these relationships. We extend previous research by differentiating by specific child mental disorders, age group (4–11 and 12–17 year-olds) and gender using data from a 2013/14 national survey of 4–17 year-olds in Australia, Young Minds Matter (N = 6310). Mental disorders were assessed using the Diagnostic Interview Schedule for Children – Version IV. Primary carer mental health problems were determined by three self-reported measures. We calculated a poverty line according to OECD standards. The greatest risk of any mental disorders when living in poverty was among 12–17 year-old males (unadjusted OR = 2.77; 95% CIs = 1.91–4.02), a significantly higher risk than for 4–11 year-old males, and particularly strong for Attention-Deficit/Hyperactivity Disorder (ADHD). By disorder type, poverty was most strongly related to Conduct Disorder (CD) and least strongly related to Major Depressive Disorder (unrelated in adolescent females). When adjusting for primary carer mental health problems, the associations between poverty and child mental disorders were not statistically significant, except among 12–17 year-old males, and for CD and ADHD in the whole sample. Further adjustment for family structure and area-level disadvantage accounted for these associations. Our results demonstrated the importance of paying attention to parental and child mental health, and the child’s developmental stage and gender when assessing the welfare, social and health service needs of families and their children living in poverty.