To address the increasing demand for mass undergraduate management education and, at the same time, a greater emphasis on student teamwork, this study outlines the development, delivery, and evaluation of a training intervention designed to build team-coaching skills in teaching assistants. Specifically, "practice-centered" and "problem-centered" techniques were used to provide teaching assistants with experiential learning opportunities to help them develop their skills. The authors evaluated the training intervention using a mixed-method multiple-data source design. Both the teaching assistants being trained as well as the student teams' experiences and perceptions of their coaches' performance were assessed. The evaluation showed that teaching assistants reported finding the program a positive experience. Importantly, students with trained coaches reported higher levels of coaching performance, team functioning, and productivity than those with untrained coaches. The implications of this intervention are discussed. (Contains 3 tables and 1 note.)