We analyzed whether a firm’s engagement in socially responsible activities, as measured by environmental, social, and corporate governance (ESG) scores, influences their tendency to avoid tax in the Korean financial market. We found a negative relationship between Korean firms’ ESG scores and tax avoidance in terms of book-tax income difference during the sample period between 2011 and 2017. This result implies that firms with good CSR performance would tend not to manipulate taxable profits, which is in line with corporate culture theory. More interestingly, this trend has become more apparent for chaebol-affiliated firms, a special type of Korean conglomerate, than non-chaebol firms.