Indonesia is a country that prioritizes the value of justice. In Indonesian ideology there is a statement “Social justice for the whole of the people of Indonesia”. However, in Indonesia there are still many people who do not get justice. For example, justice is often not fulfilled in transactions in Indonesia, one of them is cosmetic transactions. Sometimes consumers do not get exactly what they ordered or worse consumers get illegal cosmetics which contains dangerous ingredients or without marketing authorization and that would be the seller's responsibility, because in that case the seller is causing enormous losses to consumers. Therefore, legal protection for consumers is important and needed to protect consumers from sellers who are not responsible. The purpose of this research is to find out how the regulation of illegal cosmetic products are traded in Indonesia and to know the legal protection against buyer in good faith in illegal cosmetic transactions. In this research, the type of research that the author used is normative legal research with secondary data. From the research result, legal protection against buyer in good faith in illegal cosmetic transactions is law No. 8 of 1999 concerning consumer protection. Law No. 8 of 1999 protects consumers from sellers in bad faith who sell cosmetics that contain dangerous ingredients or/and without marketing authorization. Keywords : illegal cosmetic, consumer protection, legal protection Reference : 60 (2000 – 2020)