In 2014, the Association of American Medical Colleges identified 13 Core Entrustable Professional Activities for Entering Residency (Core EPAs), which are activities that entering residents might be expected to perform without direct supervision. This work included the creation of an interinstitutional concept group focused on faculty development efforts, as the processes and tools for teaching and assessing entrustability in undergraduate medical education (UME) are still evolving. In this article, the authors describe a conceptual framework for entrustment that they developed to better prepare all educators involved in entrustment decision making in UME. This framework applies to faculty with limited or longitudinal contact with medical students and to those who contribute to entrustment development or render summative entrustment decisions.The authors describe a shared mental model for entrustment that they developed, based on a critical synthesis of the EPA literature, to serve as a guide for UME faculty development efforts. This model includes four dimensions for Core EPA faculty development: (1) observation skills in authentic settings (workplace-based assessments), (2) coaching and feedback skills, (3) self-assessment and reflection skills, and (4) peer guidance skills developed through a community of practice. These dimensions form a conceptual foundation for meaningful faculty participation in entrustment decision making.The authors also differentiate between the UME learning environment and the graduate medical education learning environment to highlight distinct challenges and opportunities for faculty development in UME settings. They conclude with recommendations and research questions for future Core EPA faculty development efforts.