Gay men and lesbian women face health inequities as well as disparate treatment from healthcare providers. Stereotypes surrounding sexual health might contribute to these disparities. In five studies (N=1858), we explored sexual health stereotypes about gay men and lesbian women and their implications in prejudice/discrimination. In Studies 1, 2A, and 2B, we found people explicitly associated gay men with promiscuity and sexually transmitted infections (STIs) more than lesbian women or straight men/women. Implicitly, both gay men and lesbian women were more associated with promiscuity and STIs than straight counterparts. In Studies 3A and 3B, we tested whether these associations have consequences—finding that people express more prejudice and discrimination towards gay men and lesbian women with STIs versus those with non-STIs or straight counterparts with either disease type. Taken together, the current research identifies some psychological factors that may underpin health disparities and healthcare barriers for gay and lesbian people.