In this article, the author deals with tax liability of marketplaces in Brazil, focusing on the indirect tax charged by Brazilian states (ICMS), and its relation with the recommendations presented by the OECD and the European Union and with the other Brazilian rules, to conclude that the states’ legislation is not compatible with the Brazilian Constitution and with federal ICMS legislation. The author also briefly discusses the responsibility of marketplaces within the scope of a bill that intends to institute a federal VAT in Brazil.