Teaching self-efficacy refers to the beliefs that teachers hold about their instructional capabilities. According to Bandura’s social cognitive theory, individuals develop a sense of efficacy by attending to four sources of information: mastery experiences (i.e., performance attainments), vicarious experiences (i.e., observing social models), social persuasions (i.e., messages received from others) and physiological and affective states (e.g., stress, fatigue, mood). Personal and contextual factors also play a role in the development of teaching self-efficacy. A fundamental assumption in much of this work is that teachers who believe in their capabilities are psychologically healthier, provide better quality instruction, and are more effective in motivating their students. Unfortunately, understandings of the phenomena associated with teaching self-efficacy have been limited by poor conceptualizations and methodological shortcomings. As research on the construct has evolved, so, too, have understandings of its sources and benefits for teachers and their students.