This study examined how HIV Nondisclosure/Disclosure and Harm/No Harm to sexual partners influenced, via moral outrage and perceived threat to self and others posed by the seropositive person’s behavior, liking and trust for an HIV-positive person, stigmatization of other people with HIV, and support for a law criminalizing HIV nondisclosure. Participants were 199 undergraduate students (157 women, 40 men, 2 persons unidentified by gender). HIV Nondisclosure and Harm predicted lower liking/trust for an HIV-positive person via the perception of threat to self/others and moral outrage concerning the seropositive person’s behavior. HIV Nondisclosure predicted, via threat, personal willingness to stigmatize other people with HIV, while both HIV Nondisclosure and Harm predicted, via threat, the belief that others stigmatize people with HIV. There were no indirect effects of HIV Nondisclosure/Disclosure and Harm/No Harm on support for an HIV nondisclosure law, though HIV Nondisclosure directly predicted support for an HIV nondisclosure law. Herek’s (2002, 2014) concepts of instrumental stigma (associated with the perception of threat to self and others posed by the seropositive person’s behavior) and symbolic HIV stigma (associated with moral outrage about the seropositive person’s actions) were used to explain the results. (PsycINFO Database Record (c) 2018 APA, all rights reserved)