This study examines the effect of mandatory corporate social responsibility (CSR) on firm excess perks by exploiting China’s 2008 mandate requiring firms to disclose CSR activities with a difference-in-differences design. We find that firms mandated to report CSR experience a decrease in excess perks subsequent to the mandate. Our empirical results also reveal that the decrease in abnormal perks is more pronounced for firms with worse information environments and lower CSR disclosure quality, suggesting that mandatory CSR disclosure significantly reduces executive abnormal perks and restricts managers’ unethical behavior by improving the quality of the information environment for investors. Our main finding does not change using the subsample before 2012, indicating that the reduction of abnormal perks is driven by the enaction of mandatory CSR rather than the anti-corruption campaign started in 2012. The last but not the least, the reductions of excess perk consumption are primarily driven by non-SOE firms and competitive industries, and mandatory CSR firms are subject to a significant and stronger pay-to-performance, which again confirm the well-governed view of corporate social responsibility.