In trans women receiving hormone therapy, body fat and insulin resistance increases, with opposite effects in trans men. These metabolic alterations may affect the risk of developing type 2 diabetes in trans women and trans men. We aimed to compare the incidence of type 2 diabetes of adult trans women and trans men during hormone therapy with rates from their birth-assigned sex in the general population. Retrospective data from the Amsterdam Cohort of Gender Dysphoria with transgender individuals on hormone therapy between 1972 and 2018 were linked to a nationwide health data registry. Because no central registry of diabetes is available, the occurrence of diabetes was inferred from the first dispense of a glucose-lowering agent. Standardized incidence ratios (SIR) were computed for trans women and trans men in comparison with the same birth sex from the general population. Compared with their birth-assigned sex in the general population, no difference in the incidence of type 2 diabetes mellitus was observed in trans women (N = 2585, 90 cases; SIR 0.94; 95% CI, 0.76-1.14) or trans men (N = 1514, 32 cases; SIR 1.40; 95% CI, 0.96-1.92). Despite studies reporting an increase in insulin resistance in feminizing hormone therapy and a decrease in insulin resistance in masculinizing hormone therapy, the incidence of diabetes in transgender individuals after initiation of hormone therapy was not different compared with the general population.