People living with HIV (PLWH) who engage in substance use have worse health outcomes compared to PLWH who do not use substances. One factor responsible for this disparity is stigma. Substance involvement is seen as highly visible, disruptive, controllable, and perilous. The fact that substance use has substantial stigma associated with it may result in people assuming that PLWH who use substances have other negative attributes, and amplify stigma that PLWH who use substances face. Previous research has not systematically examined whether PLWH who use substances face different levels of stigma due to other intersecting identities and attributes compared to non-substance using PLWH. All major theories of stigma posit that stereotypes form the basis of stigmatizing attitudes. Thus, once a person is labeled as being a substance user, the person is assumed to possess stereotypical negative attributes of substance users. Therefore, we argue that compared to women living with HIV (WLWH) who do not use substances, those who use substances face higher levels of stigma and discrimination due to their other intersecting identities and characteristics (i.e., intersectional stigma). That is, stigma experienced due to multiple actual or perceived characteristics of WLWH—such as their HIV status, gender, age, race, and poverty — may be amplified for WLWH who use substances. If true, this has important implications for health, since experiencing stigma due to these identities are associated with suboptimal health outcomes, and the synergistic effects of the intersection of these multiple stigmas may be even larger. The Women’s Adherence and Visit Engagement Study (WAVE, R01MH104114), nested within the national Women’s Interagency HIV Study (WIHS) cohort of women living with HIV, assesses stigma and discrimination experienced due to HIV, gender (i.e., sexism), race, and poverty once a year for four years among 485 WLWH in four US cities (Birmingham, Jackson, San Francisco, and Atlanta). The data also include annual assessments of other psychosocial measures, viral load, medication and visit adherence, substance use, and CD4 count. We also implemented an additional data collection to assess stigma related to substance use. Leveraging these data, we propose to examine, 1) the association that substance use (non-users vs. categories of users) and substance use stigma show with profiles of experienced intersectional stigma (the combination of stigmas due to race, sex, HIV, and poverty), which in turn, leads to later substance use; 2) the mediating mechanisms in the downstream effects of substance use and intersecting stigma profiles on HIV treatment behaviors and health. The potential mechanisms we will examine include mental health (e.g., depression), interpersonal factors (e.g., social support), psychological vulnerabilities (e.g., low self-efficacy), and chronic stress (e.g., cortisol levels in hair). Findings from this research will inform tailored, comprehensive...