While the conceptual delineation between conventional and smart products is rather conspicuous, the distinction between conventional services and their smart counterparts remains elusive. This study develops a conceptual framework for understanding the distinctive attributes of smart services and their relationship to smart products. In a systematic literature review of publications from top information systems outlets, 30 contributions holding relevant information on smart services are identified and subjected to content analysis. The analysis reveals a variety of different definitions and characterizations of smart services and relations to concepts like data-driven services and services associated to smart products and smart objects. These findings are used to examine artifacts developed in rather design-oriented papers to derive five dimensions that impact the level of smartness of services: richness of the data, the knowledge intensiveness of the engine for decision support, the level of sophistication of the outcome delivered to the service user(s), the architecture of the stakeholders, and the automation level of the service processes. Within this scope, the product can have four roles: sensor, computer, interface, or integrator. The paper concludes by identifying some gaps in the overall research landscape and provides directions for future research.