This research aims to investigate the relationship between sustainability reports and the certification as a member of Thai private sector collective action against corruption (CAC) among listed companies on the Stock Exchange of Thailand. Secondary data were collected from Form 56-1 for the year 2023, totaling 546 samples. Statistical analysis, specifically logistic regression, was employed to test relationships. The findings reveal a positive association between sustainability reports and CAC membership certification. Furthermore, a detailed analysis indicated that increased environmental disclosure is associated with a higher likelihood of CAC membership certification. This research highlights the correlation between businesses prioritizing sustainable development and their emphasis on CAC membership certification. Compliance with standardized sustainability reporting and CAC membership demonstrates stakeholder engagement and responsible business operations. Anti-corruption measures foster transparency.