The degree to which infant attention behaviors, together with infant reactivity to frustrating events, predict aggressive behavior at 2.5 years, and the moderating effect of maternal behavior were tested with 64 low-risk mothers and infants. Mothers rated infant negative reactivity at 5 months and aggressive behavior and maternal trait anger at 2.5 years; infant and maternal behaviors were observed at 6 months. Based on hierarchical multiple regressions, infant attention to frustrating events at 6 months positively predicted aggressive behavior, whereas looking away from frustrating events was associated with less aggressive behavior for girls only. High reactivity to limits predicted aggressive behavior only when mothers encouraged infant attention to the frustrating event, suggesting that maternal behavior amplifies developmental pathways associated with infant temperament.