The inclusion of pastures in outdoor pig systems contributes significantly to improving the sustainability of these farming systems. This chapter examines the characteristics of pasture pig systems, including forages and pasture management as well the effects of pasture on meat quality. The chapter also provides a detailed case study of the pasture pig system developed at the Center for Environmental Farming Systems (CEFS) in the United States. Finally, the chapter looks ahead to future research in the field of sustainable pasture pig systems and provides guidance on further reading in this area.