Contemporary research suggests that transgender and gender-nonconforming (TGNC) adults encounter formidable barriers to health care, including access to quality therapeutic interventions. This systematic review is one of the first to specifically explore obstacles to TGNC mental health care. A rigorous literature review identified eight relevant studies: six qualitative designs and two quantitative designs. Thematic synthesis revealed three major barriers to care and five corresponding subthemes: (1) personal concerns, involving fear of being pathologized or stereotyped and an objection to common therapeutic practices; (2) incompetent mental health professionals, including those who are unknowledgeable, unnuanced, and unsupportive; and (3) affordability factors. Results indicate an acute need for practitioner training to ensure the psychological well-being of TGNC clients.