A study was conducted to examine the relationship between first-year teachers' self-efficacy and their participation in e-Coaching designed to positively influence development of mathematics content knowledge, development of pedagogical content knowledge, and teacher retention. Teachers who most frequently participated in e-Coaching, on average, reported lower levels of self-efficacy at the start of the school year and a greater annual gain in self-efficacy than teachers who participated in e-Coaching less frequently. Study findings suggest that with careful planning and collaboration, e-Coaching can be used as a virtual and distributed context for supporting beginning teachers' self-efficacy development.