The 2020 Korean YouTube backdoor advertising controversy refers to the practice of undisclosed or 'backdoor' advertising by Korean YouTubers and internet celebrities, involving the promotion of products without the disclosure of a paid partnership with the suppliers of these products. The discovery of this practice led to widespread controversy and the eventual involvement of the South Korean Fair Trade Commission, which imposed strict regulations on social media providers in a major crackdown. The incident also prompted calls for similar regulation in other countries, such as the United States and Japan.