Abstract
Until now, there is no consensus among researchers either about the factors influencing internal auditing and how it can be measured, or the best framework for internal audit effectiveness. This could be partly related to lack of sufficient attention to the theories. This paper extends the literature of internal auditing, and its originality is the argument that agency theory, institutional theory and communication theory could serve as an approach to build a theoretical framework of internal audit effectiveness. Moreover, this study argues that the internal audit effectiveness is impacted directly by internal auditors’ characteristics and internal audit department performance, as well as organization members’ support is a moderating variable on these relationships, which could provide insights for future research.