This study aims to examine the effect of mechanisms good corporate governance (consisting of institutional ownership and managerial ownership), cash flow volatility and investment opportunity set (IOS) on earnings quality. The population in this study was companies with manufacturing types listed on the Indonesia Stock Exchange in the period 2013 to 2017. The sample obtained using the purposive random sampling method was 130 data. Data analysis uses multiple linear regressions. The results showed that the mechanism of good corporate governance does not affect earnings quality, but the volatility of cash flows and investment opportunity set (IOS) affect earnings quality.