This Study examined the knowledge, attitudes, and beliefs of Registered Dietitian Nutritionists (RDN’s) practicing in Maine, New Hampshire, and Vermont, regarding the transgender population. 196 RDN’s from the Commission of Dietetics Registration registry located in the tri-state area responded to an anonymous online survey. The survey used the Transgender Knowledge, Attitudes and Beliefs (T-KAB) Scale and nine true/false clinically-focused questions. Descriptive statistics and chi-square analysis were used to identify trends and associations in RDN’s knowledge, attitudes, and beliefs regarding the transgender population. Political views (p < 0.0001), years practicing (p = 0.0454), and religious commitment (p = 0.0429) were negatively associated, and health disparities awareness (p < 0.0002) was positively associated, with total T-KAB Score. RDN’s surveyed had positive attitudes and beliefs, but a low level of knowledge. Future research should focus on training and education of RDN’s, and use of the T-KAB scale to evaluate pre/post-education modules regarding nutrition care for transgender patients.