This chapter reviews research on dynamic job performance. It summarizes the empirical literature and presents conceptual and theoretical approaches of conceptualizing performance change and performance fluctuations over time. It addresses longer term performance changes, describes predictors (e.g., ability, personality) and outcomes of individual differences in these changes, and incorporates a life-span perspective. It discusses vicious and positive cycles in which performance and its outcomes reinforce one another. It presents a within-person approach that focuses on short-term performance variability within persons and describes action-related and selfregulation process models of dynamic performance. The chapter closes with a taxonomy of dynamic performance processes and a research agenda for the future.