We investigated the moderating effect of family relationships on the links between maternal postpartum depression and child symptoms in a low-risk community sample of families with 3-month-old infants (n = 57). The level of maternal depression was assessed by the Montgomery-Åsberg Depression Rating Scale from a clinical interview, child symptoms by the Symptom Check List completed by both parents, and family relationships by direct observation of father–mother–baby interactions (Lausanne Trilogue Play). Families were categorized as high coordination or low coordination from their overall coordination level throughout the play. Results showed no significant links between maternal depression level and child symptoms reported by both parents. Mothers with a high depressive level in high coordination families tended to report more symptoms in their child than did mothers with lower depressive scores, whereas this link was not found in low coordination families. Prevention perspectives and clinical implications of these results are discussed.