IT business value refers to the impact of IT on firm performance. This dissertation develops a model to explain the relationship between IT and firm performance by using the Resource-Based View (RBV) of the firm, dynamic capabilities theory, complementarity theory, and organizational culture theory. Firstly, this dissertation proposes and tests a dynamic IT capability construct, which is defined as the ability to integrate, build, and reconfigure IT-based resources and competencies to adjust to rapidly-changing environments. Including four components of IT infrastructure, human IT resources, IT-enabled intangible resources, and IT reconfigurability, dynamic IT capability proves to be a valid and reliable instrument that explains firm performance. Secondly, this dissertation finds that dynamic IT capability and organizational culture jointly predict firm performance. This dissertation makes a contribution to both academic research and management practice. Theoretically, this study integrates multiple theories to provide a comprehensive IT business value model; practically, this study provides leaders in industry with useful advice on IT/IS strategy and IT investment decision-making.