To explore the mediating roles of family resources (at the individual [parental self-efficacy], family [family resilience] and social level [social support]) and parental problem-solving skills in the association between family functioning and family adaptation in families of children with cancer. A cross-sectional study. This study recruited 318 parents of children with cancer from three tertiary hospitals in mainland China. Self-report questionnaires were used to collect data on key variables, including family functioning, parental self-efficacy, family resilience, social support, parental problem-solving skills and family adaptation. Data analyses were carried out using descriptive analysis, univariate analysis, Pearson correlation analysis, hierarchical linear regression and bootstrapping. Family functioning was significantly and positively correlated with family adaptation. Family resources (parental self-efficacy at the individual level, family resilience at the family level or social support at the social level) and parental problem-solving skills both independently mediated the relationship between family functioning and family adaptation. Additionally, family resources at all three levels mediated the relationship through their effects on cumulatively parental problem-solving skills, constructing a chain mediating model. The study underscores the significance of family functioning, family resources at the individual, family and social levels and parental problem-solving skills in promoting adaptation in families of children with cancer. It highlights the need for family-centred interventions targeted at these factors to improve family adaptation. This study extended related theories and previous studies to confirm the mediating role of family resources and parental problem-solving skills, both independently and sequentially. Moreover, parental problem-solving skills were confirmed as key elements that can be incorporated into future interventions, suggesting that problem-solving skills training may serve as a highly promising program for families of children with cancer. This study was reported according to the STROBE checklist. No Patient or Public Contribution.