System dynamics modelers face a broad spectrum of risks toward achieving project objectives.  As they gain experience, their risk identification and management capabilities increase.  By applying classification techniques from taxonomy development, the collective knowledge of previous modelers has been captured in a classification scheme for system dynamics modeling risks.  The classification scheme allows modelers to more efficiently and effectively consider modeling risks by reducing the variation in their knowledge levels.  The classification structure is focused on the steps of the system dynamics modeling methodology and the achievement of system knowledge and improvement objectives.  As part of a broader modeling risk management approach, the risk classification scheme assists modelers in identifying and prioritizing the anticipated sources of modeling risks for a project.  With that knowledge, they can more effectively identify the appropriate techniques for managing risks and then efficiently apply those techniques in a timely fashion through the entire project cycle.