The aim for this study is to analyze and to obtain empirical evidence regarding the effect of earning quality on market reactions and the influence of corporate governance machanisms on the relationship between earnings quality on market reactions. This research regress dicretionary accruals, cumulative abnormal return, unexpected earning and other variable that are proxies to the practice of corporate governance (audit committee, independent commissioner, institutional ownership, and managerial ownership) by using the CG score calculation method. This research was conducted using a purposive sampling method with multiple linear regression analysis methods of manufacturing companies in the basic and chemical industry sectors listed on the Indonesia Stock Exchange (IDX) during the 2015-2018 period. This research obtained evidence that earning quality has a significant positive effect on market reaction while corporate governance mechanism does not have a moderating influence on the relationship between earning quality and market reaction. Tujuan dari penelitian ini yaitu untuk menganalisis dan memperoleh bukti empiris mengenai pengaruh earning quality terhadap reaksi pasar serta pengaruh mekanisme corporate governance terhadap hubungan antara earning quality terhadap reaksi pasar. Penelitian ini meregresikan discretionary accruals, cumulative abnormal return, unexpected earning dan variabel-variabel yang menjadi proksi praktik corporate goverance (komite audit, komisaris independen, kepemilikan institusional, dan kepemilikan manajerial) dengan menggunakan metode perhitungan CG score. Penelitian ini dilakukan dengan metode pengambilan sampel purposive sampling dengan metode analisis regresi linear berganda terhadap perusahaan manufaktur sektor industri dasar dan kimia yang terdaftar di Bursa Efek Indonesia (BEI) selama periode 2015-2018. Berdasarkan hasil penelitian ini, diperoleh bukti bahwa earning quality berpengaruh positif signifikan terhadap reaksi pasar, sedangkan mekanime corporate governance tidak memiliki pengaruh moderasi terhadap hubungan positif antara earning quality dengan reaksi pasar.