The purpose of this study was to investigate the extent that concert band directors' self-efficacy for teaching strategies was influenced by its four sources: mastery experiences, verbal persuasions, vicarious experiences, and physiological state. A secondary purpose was to investigate possible relationships between directors' self-efficacy and self-perceptions of effective teaching. Participants were high school concert band directors (N = 610). They responded to the Concert Band Directors' Self-Efficacy for Teaching Strategies Scale, Sources of Self-Efficacy for Concert Band Teaching Scale, and a scale for effective teaching abilities. Directors' self-efficacy for teaching strategies were influenced most by mastery experiences, followed by verbal persuasions, physiological state, and vicarious experiences. Participants' self-efficacy scores associated with their experience level and the influence of each source on self-efficacy differed between early-, mid-, and late-career directors. Furthermore, participants who reported greater self-efficacy for teaching strategies also rated themselves as more confident for using effective teaching skills.