This study examined the interaction effect of firm size on the impact of the independent board, independent audit committee, institutional ownership and voluntary disclosure. The study also explored the direct impact on the association between firm size, independent board, independent audit committee, institutional ownership and voluntary disclosure. Data collected from the annual report of banking companies listed on the Indonesia Stock Exchange throughout the year of an observational study. Hypotheses developed are tested with the partial least square – structural equation modelling (PLS-SEM) methodology, and the results subsequently interpreted. The results of the study revealed a positive and significant relationship between the independent board, independent audit committee, institutional ownership and firm size on voluntary disclosure in the Indonesia Stock Exchange listed banking companies. It also found that firm size, as a moderating variable, affects institutional ownership on voluntary disclosure. The existence of an independent audit committee aims at increasing the rate of voluntary disclosure in companies. Similarly, the impact of institutional ownership on voluntary disclosure has a consequence on management performance and commitment to enhance complete disclosure of information to the general public and users of financial statements for informed decision making in large companies.