Tran Kim Ngan

Type of the article: Research Article

Abstract
This study examines the determinants of internal audit effectiveness and its impact on sustainability information disclosure in Vietnamese non-financial enterprises. Drawing on agency theory, legitimacy theory, and the International Standards for the Professional Practice of Internal Auditing, the study develops and tests a structural model linking five governance-related factors (independence, objectivity, auditor competence, the scope of internal audit activities, and management support) to internal audit effectiveness and, subsequently, to sustainability information disclosure. Enterprise size is incorporated as an explanatory and moderating variable.
Empirical data were collected through a quantitative survey of 209 managers and employees in accounting, auditing, finance, and governance positions across 103 listed non-financial enterprises. The data were analyzed using reliability analysis, factor analysis, and structural equation modeling.
The results show that management support, objectivity, audit scope, and auditor competence significantly enhance internal audit effectiveness, with management support exerting the strongest influence, while independence is not statistically significant. Furthermore, both internal audit effectiveness and enterprise size positively affect sustainability information disclosure, with enterprise size playing a more dominant role, consistent with legitimacy pressures and resource-based considerations. The findings highlight the mediating role of internal audit effectiveness in translating governance practices into improved sustainability disclosure. This study contributes to the literature by providing empirical evidence from a developing-country context and demonstrating the strategic role of internal audit in enhancing transparency and supporting sustainable development.

Acknowledgment
This study is conducted within the framework of the doctoral project subject to Decision No. 3922/QĐ-ĐHDT dated August 21, 2024, Duy Tan University, Vietnam. We would like to acknowledge the reviewers and the editor-in-chief for their assistance.