As service has become the predominant part of all advanced economies, increasing attention has been paid to conceptualizing and formulating its mathematical structure. Models that arise from service and the management of service may be broadly grouped into three main categories: (1) customer behavior models, that explain how customers react to service, (2) service quality impact models, that address the business consequences of service quality, and (3) normative service models, that prescribe how organizations should organize and manage their service. We briefly discuss the most important models in each category, which arise primarily from the Marketing, Operations, and Operations Research literatures.