As of this new and modern era, so many things can be turn into business from something that can be seen or unseen. Demands and supply play a big role to this circle of selling and buying, so to keep up with the demands that never end small business turn into a company. However a company that cannot treat their business the best way they can cannot thrive for long because even when human need is fulfill the business is about to crumble down. That’s why a company need a principle to guide how they run the business. But not all principle is a good principle, that’s when Good Corporate Governance come in to play the role. The principle of Good Corporate Governance is not a law, but it is use for making the law. So in other word a company may not follow the principle but they may violate or break the law. In order to stay in the path, a company need to put Good Corporate Governance principle to their company mind and soul. It may not be enough if the principle can only be written but there’s no authority to run that principle to be a law that divide what can and cannot do. OJK (Otoritas Jasa Keuangan) is the one who regulate and uphold the law so any companies that running their business in massive scale and there people’s money in it in form of stock or bond have to obey the rule that OJK make. It is very unfortunate that still to this day many companies still have bad rating of Good Corporate Governance. That means even when the law is uphold many companies still not sensitive to this matter especially in the capital market business. This study discusses what is Good Corporate Governance means, why is it so important and necessary to look at the principle and understand the application and implications that relate to the principle, what can OJK (Otoritas Jasa Keuangan) prevent and what penalty can be done if the law is being violated, also to learn the differences a go public company and private company.