Companies are increasingly adopting social software to support collaboration and networking. Although increasing their employees’ connectedness is a major driver for organizations to deploy enterprise social software (ESS), the social connectedness concept itself is still not sufficiently defined and conceptualized yet. Our study therefore provides a richer perspective on social connectedness’ role in an ESS context. We thus investigate (1) social connectedness’ antecedents and (2) its impact on employees’ individual performance. With a survey-based investigation among 174 employees of an international business software provider headquartered in Germany, we show that both reputation and a critical mass significantly influence employees’ social connectedness. We further find that reputation’s effect is significantly stronger than critical mass’s effect and that social connectedness influences employees’ individual performances positively. We discuss our findings in the light of psychological studies and deduce implications for theory and practice.