Quality mentorship leads to improved outcomes, including productivity and career satisfaction, for both mentees and mentors in the biomedical sciences. Inadequate mentorship has proven to be the most insurmountable obstacle in a researcher's career development, particularly for mentees from groups that are underrepresented in the biomedical sciences. For example, white investigators are more likely than racial/ethnic minority peers to win NIH R01 awards and inadequate mentoring is the primary obstacle to obtaining that funding. Despite the evidence around the importance of excellent mentorship, little is known about mentorship for researchers who focus on health disparity populations, particularly sexual and gender minorities. This gap is troubling because researchers who focus on health disparity populations are often multiply marginalized based on their own gender identity, sexual orientation, race/ethnicity, and other axes of social inequality. Evidence shows that even experienced mentors learn strategies for more effective mentoring from existing curricula (e.g., Entering Mentoring). However, these curricula do not fully address the needs of researchers who focus on health disparity populations, nor do they comprehensively address ways that mentorship can help multiply marginalized researchers (e.g., transgender women of color) overcome the systemic disadvantage they face in health disparities research. Mentorship and training are central to the R01 parent award, which is focused on sexual orientation-related disparities in obstetrical and perinatal health. In the first year of the parent award, our team adapted some of the best mentoring practices and evidence-based curricula into a program that addresses the needs of mentees focused on health disparity populations and from underrepresented groups. Under the title of the Harvard Sexual and Gender Minority Health Mentoring Program, the inaugural cohort of faculty mentors piloted this curriculum in spring 2022 through a series of six 90-minute professional development sessions. The curriculum is structured around seven core competencies (e.g., aligning mentor-mentee expectations, maintaining effective communication, addressing equity and inclusion). While we collected rich evaluation data in this pilot, we do not have the resources to evaluate that data, nor to disseminate the curriculum. However, with the support of this administrative supplement, we can meet our proiect obiective to evaluate, refine, and disseminate the curriculum, Additionally, we will develop two, parallel mentor training curricula for other constituencies-postdoctoral fellows and students. Along with faculty, these groups are critical to changing the current mentorship culture from one that is ad hoc to one that is intentional, inclusive, and effective. This project will produce the first mentor training program focused on sexual and gender minority health which will bolster the next generation of health disparities resea...