Legal culture is the most difficult element of the legal system to form because it requires a relatively long period of time. This happens because culture is related to values. What is related to values, definitely requires an internalization process so that the values are not only known, but also practiced in everyday life. In accordance with Lawrence Friedman's Legal System Theory, the elements being compared are elements of legal substance, legal structure, and legal culture from the aspect of imposing interest on online loans. The attitude of online loan platform organizers, creditors and debtors towards the imposition of loan interest. This is the concern in discussing this legal issue from the aspect of legal culture. Highlighting the legal culture that has emerged around the issue of imposing online loan interest in Indonesia, the United States, and in China. In Indonesia, it is based on the interest rate set by APFI (Indonesian Fintech Joint Funding Association) which is 0.4% per day. The United States refers to the interest rate set by the Fed, which is 0.75% to 1%, and China applies loan interest at 8% to 10% per year.