Internal audit quality is one of the key factors in achieving superior organizational performance. However, upon all the existence of internal audit (IA) departments in Nigerian federal universities, poor internal control and ineffectiveness in the financial operations were identified. Therefore, this study examined the relationship between internal audit quality dimensions consisting of IA competence, IA independence, IA size, IA reporting line and timeliness of IA report and organizational performance with moderating effect of top management support in Nigerian federal universities. A total of 600 samples of internal auditors were drawn from 40 Nigerian federal universities. Data was collected using questionnaires, of which 313 responses were analysed through descriptive and inferential statistics for testing the hypotheses. The result of direct relationship of the constructs of the study reveals that there are positive relationships between IA competence, timeliness of IA report, IA reporting line and top management support with organizational performance. However, negative relationships between IA independence and IA size were identified. The result of moderating effect of top management support reveals that IA independence, IA size and IA competence produced positive and significant relationship with organizational performance. While, negative relationships between IA reporting line and timeliness of IA report were identified. The practical and the theoretical contributions of this study indicates that stewardship theory and resource dependency theory are important in explaining the effect of top management support to organizational performance. The result further implies that Nigerian federal universities are capable of achieving high level of performance with new policy initiatives by the regulatory Agencies and support from top management for IA independence, IA competent and good sizeable number of IA staff. The study also contributed to the literature of internal audit quality and organizational performance relationships with moderating effect of top management support and the IA practice in Nigerian
