Context: This research focuses on the impact of HIV/AIDS on transgender communities, aiming to assess their knowledge, attitudes, perceptions of risk, and practices concerning HIV/AIDS. Evidence Acquisition: During this systematic review, a variety of keywords, including HIV, AIDS, knowledge, attitudes, practices, behavior, action, risk perception, perceived risk, risk susceptibility, severity perception, perceived self-efficacy, cues to action, benefit, barrier, health belief model, sexually transmitted disease, sexually transmitted infection, alcohol, drugs, amphetamine, opium, trans, transgender, transsexual, gender dysphoria were used. From Scopus, PubMed, Web of Science (ISI), and Google Scholar databases, 805 articles were initially identified and screened based on their titles, abstracts, and full texts. Exclusions were made for articles not in English and grey literature. Ultimately, 13 full-text articles met the selection criteria, adhering to COREQ and STROBE guidelines. Results: The review encompassed studies involving 3,252 transgender participants. Among these, five articles evaluated knowledge levels, nearly all addressed attitudes (including perceived threats by 12 articles, perceived benefits/self-efficacy by three, and perceived barriers by seven), and 11 examined behaviors related to HIV/AIDS. The findings indicate a generally high level of knowledge about HIV/AIDS among transgender individuals, with peer health promoters playing a significant role in enhancing knowledge and facilitating access to health services. The perceived risk and severity of HIV/AIDS varied, with 52 - 82% acknowledging a perceived risk and 25 - 65% understanding the severity. The perceived benefits of HIV prevention were generally rated high, though self-efficacy in preventing HIV ranged from low to high. Barriers to HIV testing and accessing appropriate care were identified, including discrimination, distrust in health staff, lack of guidelines, and fear of test results or treatment side effects, among others. Risky sexual behaviors were common, with two-thirds engaging in such practices, 20% reporting 3 - 51 sexual partners, up to 91% having unprotected sex, around 60% using alcohol or drugs, 21 - 45% experiencing rape, and 14 - 68% being HIV-positive. Conclusions: In conclusion, the transgender community remains overlooked. Despite an adequate knowledge level and a moderate perception of HIV/AIDS risk, the prevalence of risky sexual behaviors and significant barriers to accessing health services highlight the urgent need for establishing long-term healthcare facilities and an effective surveillance system for this marginalized group.