Residents serve as educators who teach patients, medical students, fellow residents, and other medical personnel while being trained as learners. The purpose of this study was to review the literature on the competencies, perceptions, and educational status of residents as teachers, and to suggest appropriate competencies and curricular components. A literature review was conducted and resident-related institutional homepages were searched. Many countries are developing the educational competencies of residents as teachers and implementing educational programs. Residents most often taught clinical knowledge and clinical skills to patients, medical students, fellow residents, and other medical professionals, and recognized the importance of education, the joy of teaching, and the role of teachers; however, the task of teaching was burdensome. Based on these findings, competencies and educational programs for the resident as teacher are proposed. The competencies consist of the five stages of ACCESS (active learner, clinical teacher, curriculum developer, educational scholar, social communicator, supervisor/leader), and specific teaching content, methods, and assessment methods are suggested to develop these competencies. Educating residents to develop their competencies as teachers is very important as a way to foster lifelong learning skills, help others, and assist in leadership roles.