Introduction: Transgender, gender diverse, and non-binary people (TGDNB) access mental health services more frequently compared to the cisgender population, yet they continue to experience significant unmet mental health needs. The present study examined rates of mental health service use, satisfaction with services, barriers to service access, and help-seeking intentions in a sample of TGDNB adults in Australia. In addition, we examined whether barriers to service access were associated with help-seeking intentions. Methods: Participants were 150 TGDNB adults (Mage = 37.19, SD = 15.73) who reported transfeminine (n = 77), transmasculine (n = 37), or non-binary (n = 36) genders. Self-reported recency of service use, satisfaction with services, barriers to service access, and help-seeking intentions were obtained in an online questionnaire, completed in 2016. Results: Most participants had accessed mental health services in the past 6 months (55.3%). However, less than two thirds were either very satisfied (28%) or somewhat satisfied (32.7%) with these services. Common barriers to accessing services included a lack of professionals adequately trained and competent to work with TGDNB people, the cost of services, and concern with being treated poorly. Barriers to accessing services were negatively associated with help-seeking intentions, and stigma-related barriers had a greater negative effect on help-seeking intentions when satisfaction with prior services was low. Conclusions: TGDNB adults face multiple barriers to accessing mental health services, many of which appear to predict help-seeking intentions. Policy Implications: Implications and future research directions are discussed, with particular emphasis on ways to reduce barriers to service access for TGDNB adults.