There is need for closer examination of how counselors’ efficacy beliefs develop and function within actual counseling or supervisory relationships. We adapted Lent and Lopez’s (2002) model of relational efficacy beliefs to the context of counseling supervision, examining possible linkages of counselors’ self-efficacy to beliefs about how their supervisor perceives their (counselors’) efficacy (termed relation-inferred self-efficacy [RISE]), beliefs about the supervisor’s efficacy (other-efficacy), and perceptions of the supervisory working alliance. Two hundred forty graduate student counselors completed the relational efficacy belief measures in relation to a particularly challenging client on their caseloads. Path analysis findings suggested that the hypothesized model provided good fit to the data. In particular, counselors’ RISE beliefs regarding their supervisors were well-predicted by the supervisory working alliance, other-efficacy beliefs about the supervisor, amount of clinical experience, and perceived client distress level. RISE beliefs (along with amount of clinical experience), in turn, predicted counselors’ self-efficacy. In addition, the strength of the relationship between RISE and counselor self-efficacy was moderated by other-efficacy, suggesting that supervisors’ clinical credibility, from the perspective of their supervisees, plays an important role in their ability to promote the efficacy of their supervisees.