The presence of a Gender and Sexuality Alliance (GSA) reduces risk for sexual and gender minority (SGM) youth across a variety of domains, but little is known about the adult advisor-level variables contributing to these observed benefits. This study explored relationships between advisors’ tenure, receipt of professional development, self-efficacy, and social emotional competencies (SECs). Participants (N = 167) completed an online survey measuring their own social-emotional competencies and their perceived self-efficacy as a GSA advisor. As hypothesized, results demonstrated relationships between advisor tenure and self-efficacy and between advisor receipt of professional development and self-efficacy. Further, advisor SEC significantly predicted self-efficacy, and both receipt of professional development and SEC positively predicted perceived self-efficacy, as well. Findings point to opportunities for providing training to GSA advisors, with a focus on SEC to increase their efficacy in working with SGM youth. Implications for school psychologists are discussed.