Purpose: This paper aims to explore the effect of social ties on the relationship between corporate social responsibility (CSR) and firm performance in Korea. Design/methodology/approach: Social ties were measured from firm disclosures of 318 Korean firms from 2012 to 2015. Propensity score matching and regression analysis were used to investigate the moderating effects of social ties on the relationship between CSR and firm performance. Findings: The result shows that social ties have more negative moderating effects on the relationship between CSR and firm performance in Chaebol firms than in non-Chaebol firms. Practical implications: Firms need to enhance the monitoring of social ties within board members to assure the proper oversight of CSR. Originality/value: This paper contributes to the CSR literature by providing empirical evidence of the negative aspects of social ties on the relationship between CSR and firm performance in Korea.