Indonesia in this undeniably progressed period, an ever increasing number of individuals are know about web based trading exchanges. Shopee is one of the online buying and selling service providers in Indonesia, where the role of online buying and selling has grown rapidly since the covid pandemic. Shopee is one of the preferred marketplaces for Indonesians; however, due to the large number of people registering to become sellers there, violations of the law do occur. A seller who sells at shopee suffers a loss because admin fees are deducted in violation of the agreement between the seller and shopee. As a result, shopee may be considered to have committed an illegal act in the form of default, as was the case in this study. The research in this thesis employs normative research techniques and relies on three (three) legal entities to back up the data. The legal principle approach involves examining all laws and regulations pertaining to legal protection for market sellers who suffer harm. The study's findings indicate that Shopee, a marketplace service provider, has violated the terms of the agreement by cutting administrative fees. Naturally, this hurts market sellers, so they need legal protection. The Civil Code and Law No. Law No. 11 of 2008 on Information and Electronic Transactions, as well as Regulation No. 8 of 1999 on Consumer Protection, Government Regulation No. 71 on Implementation of the and Electronic Transactions, are deemed capable of safeguarding the rights of market sellers. This study also aims to determine whether the marketplace as a service provider can be subject to sanctions if it is determined that it has committed an illegal act; however, the aforementioned regulations are deemed insufficient to safeguard the rights of marketplace sellers. So that by directing this exploration, the market can survey guidelines that are thought of as one-sided and will generally hurt dealers and as contribution to the public authority to make or change guidelines for the security of venders in the market so their privileges can be completely safeguarded.