IS staff interact with their non-IS colleagues for many reasons, such as investigating their IT needs, confirming system specifications, and during testing and training. These interactions build relationships that are relied upon when non-IS employees face challenges with using IT, manifested in the informal interaction between these two groups of employees. The IS literature has argued for the importance of better linkages between IS and business employees to build shared understanding and cross-domain knowledge, so as to enhance the level of business-IS alignment in an organization. However, most research has focused on improving the quality and frequency of communications. Very few studies have discussed the specific informal activities IS staff carry out to aid their non-IS colleagues. This limited attention on the behaviours of IS employees restricts our understanding of how positive interaction between IS and non-IS employees can be encouraged and how it affects the IS department’s performance. Drawing on the concept of organizational citizenship behaviour (OCB), we derive a set of IS-specific OCB by reviewing the literature and relate them to characteristics of IS departments and IS employees. Our research questions are: a) when is IS-specific OCB more likely to occur? How does IS-specific OCB affect the performance and reputation of the IS department or unit?