Mentoring's role in medical education is threatened by the potential abuse of mentoring relationships. Particularly affected are mentoring relationships between senior clinicians and junior doctors which lie at the heart of mentoring. To better understand and address these concerns, a systematic scoping review into prevailing accounts of ethical issues and professional lapses in mentoring is undertaken. Arksey and O'Malley's (Int J Soc Res Methodol 8(1):19-32, 2005. 10.1080/1364557032000119616) methodological framework for conducting scoping reviews was employed to explore the scope of ethical concerns in mentoring in general medicine. Databases searched included PubMed, ScienceDirect, ERIC, Embase, Scopus, Mednar and OpenGrey. 3391 abstracts were identified from the initial search after removal of duplicates, 412 full-text articles were reviewed, 98 articles were included and thematically analysed. Unsatisfactory matching, misaligned expectations, inadequate mentor training, cursory codes of conduct, sketchy standards of practice, meagre oversight and unstructured processes have been identified as potential causes for ethical and professional breaches in mentoring practice. Changes in how professionalism is viewed suggest further studies of educational culture should also be carried out. The host organization plays a major role in establishing codes of conduct, expectations, and holistically, longitudinally oversight of the mentoring process and mentoring relationships.