This study investigates the financial determinants of ESG disclosures among firms listed on the Thailand Stock Market. Specifically, the study examines the influence of profitability, financial effectiveness, market valuation, financial debt, and company magnitude on the degree of ESG disclosure. By employing a dataset of 385 firm-year data points from 77 organizations over a five-year duration (2018–2022), the investigation utilizes descriptive metrics, correlation examination, and multiple regression analysis to evaluate five suppositions associated with these financial determinants. The primary discoveries demonstrate that profitability, notably measured by Earnings Per Share (EPS), and financial effectiveness, denoted by revenue expansion, positively affect ESG disclosure levels. Company magnitude also consistently displays a noteworthy positive effect on ESG reporting across all classifications. Conversely, financial debt demonstrates a blended effect; it is negatively linked with ESG disclosures for average-ranked companies (Rank B) but positively for lesser-ranked companies (Rank C). These outcomes are in accordance with the resource-based theory, proposing that businesses with larger assets are better positioned to partake in thorough ESG reporting, and the Agency Theory clarifies the intricate association between financial debt and ESG disclosures. The practical implications of these findings are significant, as they provide firms and policymakers with actionable insights to enhance ESG openness and answerability, thereby contributing to a more sustainable and responsible business environment.