This study tested whether high counseling self-efficacy was associated with less physiologic stress for student helpers facing difficult helping situations. A total of 225 students completed a counseling self-efficacy measure before providing supportive help. During this time, participants' blood pressure and heart rate were evaluated. Between the time that participants learned about their upcoming roles as student helpers and began experiencing session-management problems, diastolic blood pressure decreased for those with high self-efficacy, but not for those with low self-efficacy. The results suggest that mental health agencies may consider utilizing counseling self-efficacy measures to identify and develop capable student helpers.