ABSTRACT: Earnings information is one of the important information for stakeholders that is used asconsideration in making economic decisions. If the reported earnings are qualifed and relevant, it is expectedthat the market will react quickly after the announcement is received. The strong market reaction to earningsinformation is reflected in the value of Earnings Response Coefficint (ERC). The aims of this study is to get theempirical evidenceof The Effect of the Component of Good Corporate Governance, Leverage, and Firm Size inthe Earnings Response Coefficient. The sample of this study was 48 firms for five years 2014-2018 in theIndonesia Stock Exchange with non-probability sampling method and purposive sampling technique.Collectingdata with non-participant observation methods. The data analysis technique used is multiple linear regression.Based on the results of Leverage testing having a positive and significant effect, firm size has no significantpositive effect, the board of directors has no significant positive effect, the audit committee has a significantpositive effect and institutional ownership has no significant positive effect on the Eatnings ResponseCoefficient.Keywords : Good corporate governance, firm size