In the United States, racial/ethnic and sexual youth and young adults (YYA) of color are disproportionately affected by HIV. Subsequently, YYA experience HIV stigma and engage in increased risk behaviors and reduced HIV testing. HIV communication has been identified as a potential buffer to HIV stigma, resulting in health-seeking behaviors, such as HIV testing. In this study, we respond to a meaningful gap in the literature by examining different types of HIV communication and their impact on HIV stigma and HIV testing in a diverse sample of YYA. We analyzed secondary data from the Kaiser Family Foundation National Survey of Teens and Young Adults on HIV/AIDS. A 40-question, web-based survey was conducted with 1437 youth (ages 15–24). Recruitment included a dual sampling method from households with: (1) listed phone numbers, (2) unlisted phone numbers, (3) telephones, (4) no telephone, and (5) only cell phone access. The purpose of the survey was to establish participants’ HIV knowledge, communication, experiences, and testing behaviors. Findings suggested an association between intimate-partner HIV communication, increased HIV testing, and reduced HIV stigma. We also identified differentials in HIV testing and stigma based on gender, income, age, and sexual minority status, explained by HIV communication. Further research is needed that examines ways to use intimate-partner HIV communication to reduce stigma and increase HIV testing among YYA of different sociodemographic characteristics and sexual orientations.