Maternal postpartum depression, maternal sensitivity, and family functioning were examined as predictors of the stability of observed infant temperament over the first 30 months of life (N = 147 families). Eight observations at 8, 15, and 30 months postpartum were used to assess infant temperament. Structured clinical interviews were used to assess maternal depression, and observational assessments were used to assess family functioning and maternal sensitivity. Family context moderated the effect of maternal depression on change in infant temperament. Maternal depression was associated with change in infant temperament when maternal sensitivity was low but not when maternal sensitivity was high. Family functioning similarly moderated these links. Results underscore the centrality of the family context in shaping child behavior over time.