<p>The study examined coming-out milestones related to sexual orientation and gender identity among adult patients, including trans women, trans men, and nonbinary individuals. 129 patients (50.4% trans women, 27.1% trans men, 22.5% nonbinary; aged 18–58) were recruited from the clinical center “Be as You Are” of Sapienza University of Rome, Italy. Participants completed questionnaires assessing primary coming out milestones—awareness, self-definition, and first disclosure—for both sexual orientation and gender identity. Participants reported that awareness of sexual orientation typically emerged around age 11, while awareness of gender identity developed later, around ages 13–14. The results indicated that awareness of sexual orientation and gender identity occurred earlier than both their definition and first disclosure, with no differences among trans women, trans men, and nonbinary patients. Patients reported waiting until around 16–17 to self-define their sexual orientation, and until around 19–20 to self-define their gender identity. The majority of the sample (66.7%) first came out as LGB+ before disclosing their trans or nonbinary gender identity, while 33.3% disclosed their gender identity directly. In particular, trans women were more frequently in the group who come out only regarding gender identity (45.5%), compared to trans men (28.6%) and nonbinary individuals (10.7%). In contrast, trans men and nonbinary individuals were more likely to follow the ‘sexual orientation first, gender identity later’ pathway. These findings indicate that coming out processes for sexual orientation and gender identity, although distinct, represent interconnected developmental trajectories, with sexual orientation disclosure typically occurring first. The results emphasize the importance of considering the coming out milestones, distinguishing sexual orientation and gender identity in research and clinical practice to provide comprehensive support for trans and nonbinary individuals.</p>