Counseling graduate students may begin practicum with low self-efficacy regarding their counseling abilities and skills. In the current study, we implemented a small-series (N = 11) single-case research design to assess the effectiveness of the practicum experience to increase counseling students' self-efficacy. Analysis of participants' scores on the Counselor Activity Self-Efficacy Scale yielded treatment effects indicating that the practicum experience encompassing direct services, group supervision, and triadic supervision may be effective for increasing counselor self-efficacy. Given that the practicum experience with triadic supervision was a promising approach for improving counseling graduate students' self-efficacy, we provide implications for counselor educators to integrate triadic supervision and self-efficacy to the forefront of discussions.