Sexual function in transgender adolescents after puberty suppression has been a topic of recent clinical and scientific questions. This study aimed to explore the long-term effects of early treatment with puberty suppression on sexual functioning of transfeminine individuals after vaginoplasty. This retrospective cohort study included 37 transfeminine individuals treated with a gonadotropin-releasing hormone agonist (puberty suppression), estrogen, and vaginoplasty (penile inversion technique or intestinal vaginoplasty) at the Center of Expertise on Gender Dysphoria in Amsterdam, the Netherlands, between 2000 and 2016. Experiences regarding sexual functioning and difficulties were assessed with a self-developed questionnaire ~1.5years after genital gender-affirming surgery and compared between early (Tanner stage G2-3) and late (Tanner stage G4-5) treatment with puberty suppression. Following surgery, 91% of transfeminine individuals was able to experience sexual desire, 86% experienced arousal, and 78% could attain an orgasm. Seventy-five percent of transfeminine individuals who had not experienced an orgasm pre-surgery were able to experience one post-surgery. Of all participants, 62% reported having tried penile-vaginal intercourse post-surgery. The majority reported the presence of one or multiple sexual challenges. There were no significant differences in postoperative sexual function or sexual difficulties between groups treated with early versus late puberty suppression. With these findings, more adequate and tailored information on the expected effects of early endocrine gender-affirming treatment (including puberty suppression) can be given by healthcare professionals. This is the first study that has assessed sexual functioning of transgender individuals treated with puberty suppression, and has differentiated between the pubertal stage at treatment initiation. Limitations were the small cohort size and retrospective study design. This study focuses on sexual functioning, however, it is important to realize sexual wellbeing is multifactorial and encompasses more than genital functioning or the ability to have certain sexual experiences. This study found that post-vaginoplasty transfeminine individuals after both early and late suppression of puberty have the ability to experience sexual desire and arousal, and to achieve orgasms. Outcomes are comparable to previous findings in those who started treatment in adulthood.