We explored whether reports of three dyadic relationships (marital/partner, parent-child, sibling) were related to perceptions of family functioning in 467 mothers of children with intellectual disability aged 4-15 years. Structural equation models were fitted to examine associations between relationship indicators and family functioning. The final structural model showed that partner relationship satisfaction, partner disagreement, child-parent conflict, and sibling relationship warmth accounted for the most variance in family functioning, with partner relationship satisfaction having the strongest positive association. Dimensions of dyadic relationships appear to be associated with broader constructs of family functioning in this sample of mothers, signifying the potential for systemic intervention.