To innovate, firms need to share knowledge across their different functions. An increasing number of organizations are using enterprise social networking (ESN) for knowledge sharing internally because it is more effective than traditional knowledge management systems. However, ESN use can also have some negative outcomes; for example, it may distract employees from their work and overload them with information, while also providing a channel for leaking confidential information. This study aims to understand how knowledge sharing through ESN affects the level of innovation in firms from the service industry and how this relationship is affected by the governance of ESN. Using data from a survey of 104 participants from global financial firms, we find that the level of innovation in firms is enhanced by the use of ESN for knowledge sharing, and that governance positively moderates this relationship. The paper concludes with some theoretical and practical contributions.