Social media enables information sharing and social interaction within organization. This research aims to analyze how both work- and nonwork-related communication with colleagues and the work community on social media is associated with work engagement among Finnish professionals. A total of five Finnish professional organizations (N = 563) and a representative sample of the Finnish working population (N = 1817) contributed to the survey data, which was analyzed with structural equation modeling. We found a direct positive association between work-related communication and work engagement among Finnish working population, and a positive indirect associations between both work- and nonwork-related communication and work engagement via organizational identification and social support. Findings suggest that communication in social media supports work engagement via organizational identification and social support. Organizations should pay more attention to social media communication practices and provide opportunities to build organizational identification and receive social support in social media.