In recent years, there has been an increased implementation of massive open online courses (MOOCs). This teaching model plays a pivotal role in online education because it can provide high-quality learning resources to numerous students with great feasibility, shaping training courses according to their different learning requirements. Although the widespread adoption of MOOCs in medical education has led to numerous benefits for undergraduate and graduate doctors, their role remains unclear, suggesting the need to analyze the key factors of such a learning method in this field. To achieve this aim, a scoping review, in line with the PRISMA method for qualitative synthesis, was performed by considering studies published from 2016 to 2021, written in English, and including the physician population. Through this literature analysis, the following main areas of interest came to light: (1) pedagogical approaches, (2) MOOC structure-related variables, (3) participant-related variables, and (4) MOOCs vs. traditional courses. The review provides valuable evidence on factors underlying MOOCs effectiveness, which might be helpful for academic and healthcare organizations in designing effective training courses for physicians.