Introduction: Final year emergency medicine residents may be transitioning to practice with little to no training on how to effectively supervise and assess trainees. It remains unclear how comfortable final year residents and new-to-practice physicians are with these competencies. The goal of our study was to examine physician comfort with supervision and assessment, whether there was a perceived need for formal training in these areas, and what gaps, barriers and enablers would exist in implementing it. Methods: Qualitative data were collected in two phases during September 2016-November 2017 through interviews of PGY5 emergency residents and new-to-practice staff at the University of Toronto and McMaster University in Ontario, Canada. A semi-structured interview guide was developed and used during the first round of interviews at the University of Toronto during phase one. Results from phase one were used to refine the interview guide, to be used in phase two, to ensure that all potential areas of thematic generation were touched upon. Phase two occurred at the University of Toronto and McMaster University using the refined interview guide. All transcripts were coded, analyzed, and collapsed into themes. Data analysis was guided by a constructivist grounded theory based in a relativist paradigm. Results: Thematic analysis revealed five themes. Residents and staff alike described acquiring the skills of supervision and assessment passively, primarily through modeling the behaviours of others; the training that is available in these areas is variably used, creating a diversity of physician comfort levels within these two competencies; the many competing priorities in the emergency department represent significant barriers to improving supervision and assessment; providing negative feedback is universally difficult and often avoided, sometimes resulting in struggling trainees not being identified until late in residency; the move towards competency based education (CBE) will act as an impetus for more formal curriculum being required in these areas. Conclusion: As residency programs transition to a CBE model, there will be a greater need for formal training in supervision and assessment to achieve a standard level of comfort and competence among senior residents physicians in independent practice. These competencies will also need an emphasis on how to identify struggling trainees, and how to approach negative and constructive feedback.