Service Science is an emerging interdisciplinary field to systematically improve the design and innovation of service. Although many of the concepts used in service science have been around for some decades, this term is usually associated with an initiative called Service Science, Management, and Engineering (SSME), led by IBM in the first half of the 2000s to advance service research and education (in this entry, Service Science and SSME are considered synonymous, but the shorter term will be used here). Service Science is receiving growing attention due to the rising importance of service industries in world economies. The relevance of this topic is also justified because it helps organizations improve service performance, including service quality. This entry describes the key drivers, analyzes the evolution, examines the theoretical underpinnings, and defines Service Science. It concludes with a brief discussion of the challenges facing Service Science.