LGBT inclusive sex education is one way to address health disparities that exist between students who identify as LGBT and those who identify as heterosexual and cisgender. This study examined the inclusivity of sex education in Montana's high schools and the challenges faced by teachers in providing sex education that is relevant for LGBT youth. Data were collected via electronic questionnaires from 237 young adult alumni of Montana's high schools, about half of whom identified as LGBT, and 64 health enhancement teachers tasked with teaching sex education. Nearly 90% of respondents rated the nine sex education topics listed on the questionnaire as "somewhat or very important." While the importance of sex education was affirmed by most of the young adults and teachers represented in this study, fewer than 30% recalled topics related to LGBT sexual health being "fully covered." Lack of teacher training was the most salient factor related to the paucity of coverage. Meeting the needs of all students in Montana's schools requires professional training and development for teachers that includes a focus on delivering inclusive, comprehensive sex education.