This paper investigates the key factors influencing service innovation in the context of knowledge-intensive businesses. By taking the perspective of the knowledge-based view and applying dynamic capability theory, we develop a theoretical model to investigate the role of knowledge conversion (from tacit knowledge to explicit knowledge), service standardization capability, and value co-creation in service innovation. The related hypotheses are tested by using survey data from knowledge-intensive service firms that have already been involved in service innovation. We applied partial least squares analyses, and the results suggest that knowledge conversion is positively associated with service standardization capability, and that service standardization capability positively moderates the effect of value co-creation on service innovation. This study makes theoretical contributions to the service innovation field by revealing the process of how converted knowledge helps service standardization and how standardized service interacts with value co-creation. Related practical implications and methodological contributions are also discussed.