Health locus of control (HLC) beliefs may influence the health behaviors that patients perform on their own behalf. Likewise, the HLC beliefs that clinicians consider desirable may influence how active they encourage patients to be in managing health. It remains unclear how involved lung recipients want to be and how involved transplant clinicians believe they should be. The aims of this study were to describe HLC beliefs and behaviors manifested by recipients and clinicians in the setting of lung transplantation. Mixed-methods were used, including quantitative techniques to measure demographics, clinical characteristics, and HLC using the Multidimensional Health Locus of Control Scale (MHLC), and qualitative techniques to explore how HLC beliefs were manifest in the clinical setting. Nearly all participants manifested behaviors consistent with high internality and externality, highlighting the importance of holding ‘dual health locus of control’ beliefs for optimal health management and lending support for recipients and clinicians to share responsibility for managing post-transplant health.Funded by the Nursing & Social Sciences Council of the International Society of Heart and Lung Transplantation.