Aim: This present study evaluates oversight mechanisms and how they drive ESG disclosure. It specifically examines the roles of Audit Committee Effectiveness and Institutional Shareholding on the disclosure of ESG practices of non-financial firms in an emerging economy, Nigeria. 

Background: Rising forms of challenges in the field of environment, society and governance are leading to calls for adoption and disclosure of sustainable practices across the world. Despite this demand, the disclosure level varies among firms and across countries. The insufficiency of evidence about the reporting of ESG practices in emerging financial markets creates a reassuring setting to assess the influence of oversight mechanisms on crucial decisions of companies, such as ESG disclosure. 

Methodology: For this research, a longitudinal design using ex-post facto methodology was utilized. Criterion sampling was used to select the firms for the study. The data utilised in this research comprised annual reports and accounts of 39 non-financial firms listed in Nigeria from 2012 to 2021. Descriptive and inferential statistics, particularly panel data regression, were employed to analyse the results. The study involved conducting tests hausman test and redundant fixed effects. 

Findings: The research indicates that management's oversight mechanisms significantly enhance ESG information disclosure, with audit committee effectiveness and institutional ownership showing a substantial and positive impact on ESG reporting. The size of a firm and profitability were the control variables used and these demonstrated a notable positive effect on ESG disclosure.

Contribution: This study is one of the limited investigations into oversight mechanisms driving ESG disclosure in Nigeria, where evidence remains sparse. Additionally, the study incorporates an audit committee effectiveness index, which includes a comprehensive score derived from four key auditor attributes, further divided into seven components, within the setting of ESG reporting studies in Nigeria. This gives a thorough evaluation of audit  committee effectiveness, making the study particularly significant.

Recommendations: 
Researchers: The study recommends employing both quantitative and qualitative methods to examine various oversight mechanisms influencing ESG disclosure. It also suggests conducting comparative studies across different sectors to understand the variations.

Practitioners: Practitioners are advised to closely monitor oversight mechanisms that enhance ESG reporting and implement robust frameworks that prioritize transparency, accountability, and ethical practices to improve ESG disclosure.

Regulators: Clear guidelines and standards for ESG disclosures should be established to help firms understand expectations and compliance requirements. Monitoring and enforcement mechanisms should be implemented to ensure firms adhere to ESG reporting standards. 

Implications for Africa: Improving the institutional quality in African countries can support better compliance with sustainability reporting standards. Strong regulatory frameworks and increased diversity and expertise within corporate boards are necessary to enhance ESG disclosures in Africa.