Though singular or discrete service innovations are accepted as essential to the performance and survival of organizations, practitioners and researchers are increasingly directing their attention towards the firm-level capability that underlies their repeated and continuous introduction, commonly referred to as service innovation capability (SIC). However, compared to the rich body of literature on the innovation capability of manufacturers and industrial organizations, SIC is poorly understood by managers and service researchers and there is no consensus on its definition, antecedents, outcomes, or dimensions. This study remedies this protracted gap through a comprehensive review of 45 academic journals reporting on firm-level studies of SIC using the SPAR-4-SLR protocol. These were found in the Web of Science and Scopus databases and analyzed according to the TCCM framework. Our research provides new theoretical and managerial insights, advancing a consolidated original definition of SIC, reconciles and organizes factors in SIC’s nomological network advanced by disparate studies and synthesizes links between them in an integrating framework, and makes 13 propositions for advancing this topic based on the research gaps identified.