The development of financial technology (fintech) in Indonesia, particularly information technology-based lending services (peer-to-peer lending), has increased public access to financing. However, the determination of loan interest rates by the Indonesian Joint Funding Fintech Association (AFPI) raises the potential for joint price fixing practices, which are prohibited by competition law. This study aims to analyze the compliance of AFPI's determination of online loan interest rates with Article 5 paragraph (1) of Law Number 5 of 1999 and examine its legal implications for regulating the financial services sector. This study uses a normative legal research method with a statutory and conceptual approach. The results show that AFPI's determination of maximum interest rates has the potential to meet the elements of price fixing because it is a horizontal agreement between business actors that influences price determination in the online lending industry. Therefore, regulatory harmonization and strengthened supervision are needed to ensure healthy business competition and legal protection for consumers.