System dynamics (SD) is a powerful simulation method that is ideal for modeling human processes, as well as many processes that occur within the healthcare system. The SD approach has been used and validated extensively in a wide array of fields and industries. This chapter will provide an overview of the SD modeling and simulation methodology as well as provide more detailed steps related to building and validating SD models. Finally, this chapter will show a specific set of SD models related to dialysis, Kidney and Transplant Patients, Hypertension Patient Flow, and Organ Donation and Transplantation.