This research aims to examine the simultaneous effect of Corporate Governance (CG) and Market Performance (Tobin’s Q). This research also intend to investigate determinant GCG and Tobin’s Q. CG implementation is measured based on the result of an annual survey by Indonesian Institute for Corporate Governance (IICG) which is in The Report of Corporate Governance Performance Index (CGPI). The samples are listed company in Indonesian Stock Exchange which took part the survey by IICG and scored in CGPI from 2008 to 2014. This research uses 40 firm years for sample. Using 2 SLS method, this research found that growth and size have positive influence to corporate governance implementation. This research also found that DER and ROA have positive influence to Tobin's Q. There is no simultaneous result GCG and Tobin’s Q. Tobin’s Q have positive influence to corporate governance but there is no positive impact of GCG implementation to Tobin’s Q.