Youth who identify as transgender or gender non-conforming (TGNC) are at greater risk than their peers for mental health concerns. School staff knowledge and training on supporting the mental health of these students may have a significant effect on this population. To better understand where school staff are provided such training, we conducted a scoping review to determine any differences in staff knowledge and training between urban, suburban, and rural high schools. We searched five electronic databases using keywords: transgender or gender variant or gender non-conforming, mental health, school, and student. Twelve articles met the criteria for review. We found no comparative studies that differentiate staff training and knowledge across high school settings. Most articles demonstrated the efficacy of training school staff in supporting TGNC students, and demand from school staff for access to such training. School nurses can lead and advocate for such training to support TGNC students.