This study was conducted to explore the relationships between teachers' motivation toward web-based professional development, Internet self-efficacy, and beliefs about web-based learning. By gathering questionnaire data from 484 elementary school teachers, this study indicated that the teachers' Internet self-efficacy and behavioral beliefs about web-based learning were significant predictors for their motivation toward web-based professional development. The teachers with higher Internet self-efficacy and stronger beliefs about the positive consequences of web-based learning tended to express higher motivation toward web-based professional development. (Contains 8 tables.)