Public managers play a central role in the adoption and smooth implementation of social media tools in the workplace, with local governments increasingly expecting managers to utilize these tools. Nevertheless, we know little about how public managers perceive social media use for work activities and what factors shape such perceptions. Preliminary research has shown that social media use in government may enhance task efficiency, but it may also increase management complexity and workload. In this study, we draw from current literature on e-government adoption and use to investigate the role of personal and organizational use of social media, organizational culture, digital threats, and technological capacity in shaping public managers’ perceptions of social media use. Combining data from a national survey of 2,500 public managers in 500 U.S. local governments, Census data, and data collected from city websites, we find that perceptions of social media tools in the workplace are influenced by the interplay of personal and organization use of social media, an organizational culture of innovation, and formal guidance on social media use. Technological capacity and perceptions of digital threats are not significantly related to perceptions of social media. We conclude with a discussion of what these findings mean for research and practice.