The human papillomavirus (HPV) vaccine remains underused among Black female adolescents. In the study described in this case, we used mixed methods to understand factors associated with Black mothers’ intentions to vaccinate their daughters against HPV. The theory of reasoned action and health belief model were used to guide this study. This case study provides insights into designing and conducting a mixed methods sequential QUAN → Qual study using surveys and semi-structured interviews along with discussing the benefits and challenges. This case demonstrates application of this mixed methods sequential design to yield a better understanding of the research issue and the importance of engaging the community throughout study planning and implementation. This case study also provides an example of a theoretical framework when conducting a mixed methods sequential QUAN → Qual design and discusses lessons learned in using this research approach.