This study examines the effect of capital structure, investment opportunity set, and corporate governance mechanism on earnings quality. The dependent variable used in this research is earnings quality, while the independent variable is capital structure, investment opportunity set, managerial ownership, institutional ownership, audit committee and independent commissioner. Samples in this study are the manufacturing companies listed in the Indonesia Stock Exchange during 2012-2016. Data collected by purposive sampling method. The analysis method used is multiple regression analysis. The result of analysis showed that capital structure, institutional ownership, audit committee and independent commissioner have no effect on earnings quality. While investment opportunity set and manajerial ownership has a negative effect on earnings quality.