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. Understandings of teaching self-efficacy, its sources and its effects, have been limited by poor conceptualizations and methodological shortcomings. Nonetheless, researchers have provided ample evidence that teachers with a high sense of efficacy tend to be more psychologically healthy and effective than teachers who doubt their capabilities.