Abstract Attracting and developing information technology (IT) professionals is one of the top concerns for companies. Although much research has been conducted about the job behavior and attitudes of IT professionals over the last three decades, findings are inconclusive and contradictory. This suggests that something may be missing in how we examine this phenomenon. Most of this research is drawn from theories of motivation, very little examines the effect of social relationships on IT professionals' behavior and attitude. Yet, social capital theory suggests that job behavior and attitude may be greatly influenced by these relationships. This suggests that IT professionals' social capital warrants empirical examination. The primary research question that this dissertation addresses is how social capital affects IT professionals' work attitude and behavior including job satisfaction, organizational citizenship behavior, job performance and turnover intention. The research model in this dissertation examines the influence of three aspects of social capital on IT professionals' job attitude and work behavior: tie strength, the number of ties and the structural holes. Data were collected from 129 IT professionals from a range of jobs, organizations and industries. Results indicate that tie strength in the organization of an IT professional is positively related to job …