While transgender women have been identified as a global priority population for HIV prevention and treatment, little is known about the cisgender male partners of transgender women, including their sexual behavior and HIV prevalence. Previous research has suggested that these male partners have varied identities and sexual behavior, which make identifying and engaging them in research difficult. This paper describes interviews conducted with fifteen cisgender men who reported recent sexual activity with transgender women in Lima, Peru. The purpose of this research was to explore how these men reported their identities and sexual behavior, to better understand how they would interact with HIV outreach, research, and care. The major themes were sexual orientation and identity; view of transgender partners; social ties to transgender women and other men with transgender women partners; disclosure of relationships; HIV knowledge and risk perception; and attitudes toward interventions. We found that language used to assess sexual orientation was problematic in this population, due to lack of consistency between orientation and reported behavior, and unfamiliarity with terms used to describe sexual orientation. In addition, stigma, lack of knowledge of HIV prevention methods, and fear of disclosure of sexual behavior were identified as barriers that could impact engagement in HIV research, prevention, and care. However, participants reported social relationships with both transgender women and other men who have transgender partners, presenting possible avenues for recruitment into HIV research and healthcare services.