Trans women are at high risk of HIV infection. We conducted a review to determine the extent to which trans women were eligible for inclusion in and enrolled into pre-exposure prophylaxis (PrEP) efficacy trials. Out of seven trials analyzing PrEP efficacy, we found that trans women comprised only 1.2% of one trial and 0.2% of total trial enrollments. Although an additional PrEP trial to determine efficacy among trans women may not be warranted, further research is needed to determine the effectiveness of PrEP in this marginalized population, through observational and feasibility studies. These studies should focus on unique barriers that trans women may experience while obtaining access to PrEP, such as gender discrimination, transphobia, and violence.