Insider trading is one of the financial crimes that occur in the capital market which results in injustice for investors. This injustice also results in losses for investors because companies that experience insider trading show that insiders of the company are irresponsible and unaccountable. In the end, insider trading will ultimately cause investors to leave the capital market of that country and choose another country’s capital markets that are fairer. Capital market regulations in a country must be properly implemented, including regulation of insider trading. This is necessary to grow a country’s capital market by ensuring investors can be treated fairly in the capital market. In this study, there are two objectives. The first is to identify and describe the application of the disclosure principle and the fiduciary duty doctrine in the capital market laws of Indonesia, the United States of America, and the People's Republic of China. The second is to find out and explain the comparison of insider trading law enforcement in Indonesia with the United States and the People's Republic of China, which have capital markets that are more successful in terms of market capitalization than Indonesia. From the results of the research, the researchers conclude that applications and expansion of the disclosure principle and doctrine of fiduciary duty will help regulate insider trading, including learning from other countries how to enforce insider trading in the capital market.