This study investigated the influence of disease status, various family constellation and individual variables, family social support and resources, and maternal adjustment on 57 well siblings’ adjustment and adaptation for three groups of children (HIV-positive, HIV-exposed [indeterminate], and healthy comparisons) and their mothers who were HIV-positive. The study further investigated the effects of these variables on the siblings’ / children’s mothers. Findings showed that maternal adjustment difficulties were positively associated with siblings’ internalizing symptoms of adjustment and negatively associated with mothers’ perceptions of the availability of family resources. When the relationship between maternal adjustment and the mothers’ perceptions of family resources was examined, the association was found to be strongest for the HIV-exposed or indeterminate group. While most of the mothers participating in our study chose not to disclose their own or their child’s HIV / AIDS diagnoses to others, results showed sibling adjustment and adaptation not to be affected by disclosure. Finally, there was a relationship between maternal adjustment and symptoms of anxiety and depression in siblings. This finding was interpreted as supporting the role of maternal adjustment with regard to family functioning and children’s management of stress. Implications of the results are discussed in a context of the resiliency of children in the face of adverse circumstances.