This study focused on the self-efficacy and experiences described by a purposively sampled case (n = 8) of high school-aged underrepresented minority women (URMW) as they entered the medical career pipeline through their participation in a formal medical pipeline program. The study was framed by three theories: intersectionality, positionality, and self-efficacy. Research questions were analyzed qualitatively, using case study methods, and quantitatively, using a paired sample t-test. Study data revealed that participants came into the program with high levels of self-efficacy in several self-efficacy factors. Yet, participants in the pipeline program made significant improvements in their self-assertive efficacy. Analysis of other data revealed that students remained motivated and persisted in the pursuit of their aspirations in spite of challenges they encountered because of their ethnicities and gender. Also, students described a lack of engagement with science courses, indicated poor relationships with science instructors, and revealed inadequate understanding of important high science content that, along with ethnic and gendered factors, caused them to negatively position themselves in science. This study provides valuable information to K-12 science educators, medical education institutions, and policy makers concerned with extending science education and healthcare-related career opportunities to minority women.