A 1-year longitudinal study tested the model that the relation between maternal depression and adolescent suicidal symptoms is mediated by family functioning. Participants were 240 children (mean age = 11.86 years) and their mothers; 77% of the mothers had a history of a mood disorder and the remaining 23% were lifetime-free of psychopathology. An adolescent suicide index was created based on suicide items from the child and parent versions of the Children's Depression Inventory, Child Behavior Checklist and Children's Depression Rating Scale, administered at both Time 1 and 2. Family functioning was assessed with the Family Relationship Index completed by mothers and children at Time 1. Results indicated that the relation between maternal depression and adolescent suicide symptoms at Time 2 was mediated by perceived family functioning, controlling for suicide symptoms at Time 1.