The present study examined the independent and joint relations of parental self-efficacy beliefs and parent knowledge of child development to maternal behavioral competence among mothers of high-risk infants. Sixty-five mothers completed questionnaires regarding parental self-efficacy and knowledge of child development and were assessed for behavioral competence during a 10-min free-play session with their infants. There were no independent contributions of parental self-efficacy or parent knowledge of development in predicting parenting competence. However, the relation between parental self-efficacy and parenting competence was moderated by parent knowledge of development. Consistent with Bandura's ["Psychol. Rev." 84 (1977) 191; "Am. Psychol." 44 (1989) 1175] formulations, parental self-efficacy and parenting competence were positively associated when parental knowledge of development was high. By contrast, parental self-efficacy beliefs and parenting competence were inversely associated when knowledge of development was low. Mothers reporting high parental self-efficacy, but low knowledge of development, were the least sensitive with their infants in play interactions, suggesting that these mothers were naively confident about their parenting abilities. Implications for designing interventions for naively confident mothers are discussed.