Abstract Purpose: Using a sample of 1,680 observations over a period of 15 years (2007-2021), this study provides the additional evidence on the effect of chief executive officers on internal control system disclosure. Methodology/Approach/Design: A correlation research design was used and data were sourced from the annual reports and accounts of the firms. The data were analysed using descriptive statistics and multiple regression analysis. Additionally, diagnostic checks such as normality and homoscedasticity of residuals, multicollinearity and model specification error were carried out in order to ensure that the model is tested for best linear unbiased estimator. Results: The results indicate that CEO exerts a significant influence on internal control system disclosure in areas such as female gender diversity and nationality. The results also show that firm size has no significant effect on internal control system disclosure. But leverage has significant effect on internal control systems disclosure. Originality: This study points to a promising direction for future research to gain a deeper understanding of how the characteristics of the CEO affect internal control system disclosure decisions of listed firms in Nigeria. Limitations: The study is limited by the number of samples, specifically 112 listed companies. It is expected that further research can increase the total sample of companies and also by adding to the research period or using company samples from other exchanges.