PROJECT SUMMARY/ABSTRACT Candidate. Dr. Meyers-Pantele applies for this K01 mentored training award with the independent career goal of attaining a productive and independent research career as a health behavior interventionist focused on reducing HIV disparities among women who use drugs (WWUD). Her current training, however, does not extend beyond the secondary analysis of stigma, and substance use data, and is insufficient for in-depth instruction on the theoretical and practical methods required for the development and implementation of health behavior interventions for racially and ethnically diverse WWUD. Specifically, the K01 training will support her transition to an independent career scientist by: (1) developing proficiency in intersectionality theory to inform an intervention targeting HIV prevention service engagement and intersectional stigma for racially diverse WWUD, (2) gaining expertise in mHealth intervention design and development to create the proposed mHealth intervention, (3) building proficiency in the implementation of randomized controlled trials to pilot the developed intervention, (4) strengthening her skill base in implementation science to design an intervention that has the potential for adoption and implementation, and (5) fostering the personal development skills necessary for a successful academic career. These training aims will be accomplished through didactic courses, training workshops, participation in professional research networks, hands-on research, and mentored training. Research and Environment. WWUD are at increased risk for HIV and have low levels of pre-exposure prophylaxis knowledge and acceptance. Additionally, racially and ethnically diverse WWUD experience intersectional stigma due to gendered and racialized social norms surrounding womanhood, motherhood, morality, substance use, and criminality, all of which have important implications for women’s engagement with HIV prevention services. Mobile health (mHealth) interventions and interventions that target intersectional stigma have the potential to increase HIV prevention service engagement, but there is a dearth of interventions tailored toward racially diverse WWUD. The proposed research will provide Dr. Meyers-Pantele with the training to address this critical gap in HIV prevention research. She will employ qualitative methods to identify key experiences with HIV prevention services and intersectional stigma, and potential barriers and facilitators to intervention adoption and implementation, to inform the development of potential theory-driven mHealth intervention components. This information will be used to develop and test the usability of the mheaLth interventiOn To redUce Stigma (LOTUS) intervention to improve HIV prevention service engagement and intersectional stigma for racially and ethnically diverse WWUD. Lastly, she will conduct a pilot RCT to assess the feasibility, acceptability, and preliminary impact of the LOTUS intervention. Th...