The purpose of this case study was to understand and to describe the sources of self-efficacy (Bandura, 1997) for an experienced European American teacher in a suburban high school. Like other teachers who may have left teaching, this teacher had been challenged over the years. This could have threatened her sense of self-efficacy and ultimately resulted in her leaving the teaching profession. Yet she persevered. Her experiences can teach us about teacher self-efficacy and teacher persistence. Findings of this case study have implications for teacher self-efficacy theory, for future research, and for teacher retention. (Contains 2 footnotes.)