This chapter summarizes the 4-year-long PEP professional development (PD) initiative in terms of current perspectives on teacher learning and PD, shares lessons learned about the design and delivery of high-quality PD, and presents some principles to guide the development of future PD efforts. The first section reviews the definition and theoretical underpinnings of PD that guided the work. The second section presents lessons learned for the design and delivery of quality PD experiences for and with physical education teachers. The third section presents a framework for thinking about and designing future PD programming and in the final section directions for future research in PD with physical education teachers are noted.