ABSTRACTThe 2030 Agenda, represented by the Sustainable Development Goals (SDGs), signifies a global commitment to peace, prosperity, and sustainability. However, the lack of a unified strategy has slowed progress, raising concerns about meeting the 2030 deadline. Thailand's progress toward the SDGs has been influenced by various factors, including the role of the Sufficiency Economy Philosophy (SEP). This study uses corporate‐level data and Refinitiv ESG ratings as proxies for sustainability performance to assess the impact of SEP score, as a proxy for SEP disclosure, on corporate sustainability. We find that Thai firms with higher SEP scores tend to exhibit better sustainability performance, especially in the environmental and governance dimensions. Our analyses reveal a causal relationship between SEP scores and corporate sustainability performance, with a one standard deviation increase in the SEP score leading to a 35% increase in sustainability performance. The findings support our hypothesis that SEP fosters stakeholder engagement and long‐term value creation while aligning corporate strategies with sustainability goals, thereby contributing to the SDGs. Furthermore, the SEP score serves as a nonfinancial indicator that signals a firm's commitment to sustainability strategies.