Mentorship is critical to the development and professional growth of graduate medical education (GME) trainees. It is a bidirectional relationship between a mentor and a mentee. Mentorship has consistently been shown to be beneficial for both the mentor and mentee, with the mentee gaining valuable skills in education, personal growth, and professional support, and the mentor attaining higher career satisfaction and potentially greater productivity. Yet, there is a lack of research and in-depth analysis of effective mentorship and its role in postgraduate medical education. This chapter outlines different approaches toward mentorship and provides the reader with basic concepts relevant to the effective and competent practice of mentorship. The authors discuss the challenges that physician mentors and mentees face, the organizational models of mentorship, the approaches and techniques for mentorship, and the deleterious effects of mentorship malpractice. Our general discussion touches on best practices for both the mentor and mentee to allow for self-improvement and lifelong learning. The variety of applicable models makes it difficult to measure effectiveness of mentorship in GME, but there is an ongoing need for expanded research on the benefits of mentorship, as greater amount of supporting evidence will likely incentivize organizations to create mentorship-friendly policies and support corresponding institutional changes.