This work represents an improved and updated version of the jurisprudential and doctrinal elements of the Master's Dissertation in Legal and Business Sciences, presented on 12 June 2012 at the Lus?fona University of Humanities and Technologies in Lisbon. The aim of this work was to develop a study of Mozambique's tax system, with special emphasis on VAT and the problems surrounding the issue (or non-issue) of invoices. The tax system of any country is one of the fundamental points for the development of the economy, because the better it works, the more revenue the state collects and the greater the growth for the country. Mozambique's current tax system has developed considerably, especially since the introduction of Value Added Tax. However, in addition to the advantages brought by VAT, there are some obstacles that the Mozambican Tax Authority has been facing, namely the fact that taxable persons do not issue invoices.