The American School Counselor Association has placed an increased emphasis on school counselor leadership. School counselors play an essential role within the educational setting (ASCA, 2019). Leadership embodies the overarching role of a school counselor and is a key component of each school counselor's professional identity (McMahon et al., 2009), which begins to take shape during graduate school. School counselor trainees are expected to assume a leadership role immediately upon entering the professional work field. It is not known what the perceptions of school counselor trainees' leadership practices are from the school counselor trainees, and in comparison, to site supervisors at the conclusion of the school counselor trainees' internship experience, prior to entering the professional work field. This study used a quantitative comparative analysis to compare the perceptions of school counselor trainees and site supervisors who oversee school counselor trainees, regarding school counselor trainees' leadership practices. More specifically, a survey approach was used and investigated the following five key dimensions identified in the School Counseling Leadership Survey [(SCLS); (Young & Bryan, 2015)] of school counselor trainees' leadership practices: 1) interpersonal influence, 2) systemic collaboration, 3) resourceful problem solving, 4) professional efficacy, and 5) social justice advocacy. Data was analyzed using Independent-samples t-tests. The tested hypotheses found one of the five factors to be significant, interpersonal influence. There were no significant differences in site supervisors among the levels in which they work (elementary, middle, or high) or their years of experience. The findings from this study indicate avenues of future study connected to school counselor trainees' leadership practices and is important for school counselor trainees, site-supervisors, and counselor educators. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]