Based on theory that parents with higher levels of self-efficacy (PSE) should find it easier to parent effectively in the face of challenging child behaviors than should parents with lower levels of PSE, this study examines the link between PSE and parenting using children's behaviors as potential moderators. Participants were 130 parents who had an older adolescent (M (age) = 17.58) in addition to the target adolescent (M (age) = 11.79), and both adolescents' externalizing behaviors were used as moderators for the link between PSE and parenting of the target adolescent. Path analysis in Mplus showed that higher PSE was linked to more promotive parenting but only among parents who had an older adolescent with lower levels of externalizing behaviors. Among parents of adolescents with higher levels of externalizing behaviors, whose promotive parenting was significantly lower than other parents overall, PSE did not predict promotive parenting. The link between PSE and parenting did not differ depending on the target adolescents' behavior. Findings suggest that the link between parents' beliefs and parenting depends on the broader family context. More specifically, how PSE is linked to parenting practices depends at least partly on the experiences that parents bring from parenting an older adolescent to their interactions with a later-born adolescent. From a clinical perspective, parents might need guidance in how to think about their earlier parenting experiences when parenting a younger adolescent.