A developmental model of the origins of maternal self-efficacy and its impact on maternal sensitivity was tested. Participants were 92 primiparous mothers and their 6-month-old infants. Mothers completed questionnaires about remembered care from their own parents and self-esteem prenatally, satisfaction with support, infant temperament, and maternal self-efficacy postnatally, and they participated in a laboratory observation with their infants. Maternal self-efficacy was predicted by remembered maternal care as mediated by global self-esteem. Infant soothability predicted maternal self-efficacy independently and in conjunction with distress to novelty and in conjunction with both distress to limits and satisfaction with support. Maternal self-efficacy interacted with distress to limits to predict maternal sensitivity during emotionally arousing activities. High infant distress was associated with less sensitive maternal behavior when maternal self-efficacy was moderately low and extremely high, but was positively associated with sensitive maternal behavior when self-efficacy was moderately high. Implications for future research are discussed.