This paper examines how Lesson Study (Lewis, 2002) was used in an elementary mathematics methods course held at a Professional Development School and intended to support pre-service teachers to become reflective practitioners while working alongside clinical faculty. Attention is given to detailing the features of Lesson Study that situates the learning in a job-embedded setting and joint reflection as endorsed by the recommendation for "Clinical Preparation and Partnerships for Improved Student Learning" (NCATE, 2010). Findings highlight how Lesson Study at the PDS site impacted the "multi-tiered" professional development of pre-service teachers and clinical faculty, as they collectively focused on student learning, research, and inquiry. In addition, this article examines how the unique model and outcomes of Lesson Study in a Professional Development School (PDS) enhanced teacher preparation. The study offers a process for teacher educators and Professional Development Schools to use Lesson Study as a collaborative learning structure to promote reflective practice in developing effective teachers. (Contains 1 table and 1 figure.)