The United Nations Model Double Taxation Convention between Developed and Developing Countries: 2021 Update is a publication geared towards the international community especially developing countries and countries with economies in transition. Double tax treaties aim to prevent unrelieved double taxation, in order to foster cross-border economic activity and the transfer of technology. The UN Model Tax Convention consists of articles on the treaty’s scope and on definitions to be used in the treaty. For different kinds of income and capital, it allocates taxing rights before establishing how double taxation will be eliminated where the taxing rights are shared. It also includes articles that prevent certain forms of tax discrimination; provide for the exchange of tax information and assistance in tax collection between the treaty partners; allow the treaty partners to consult together, through the Mutual Agreement Procedure, to resolve disputes or address doubts concerning the treaty; and address certain types of treaty abuse. The most important changes included in the 2021 version of the UN Model address concerns expressed by developing countries regarding tax treaty obstacles to the taxation of foreign enterprises on income from automated digital services and on gains on so-called “offshore indirect transfers”. The 2021 UN Model also features new guidance on the application and interpretation of the definition of a permanent establishment, the concept of a beneficial owner, and the application of the Model’s provisions to collective investment vehicles, pensions funds, and real estate investment trusts. This fifth edition of the UN Model Tax Convention culminates four years of work by the UN Tax Committee and its Subcommittees, supported by the Secretariat in the UN Department of Economic and Social Affairs. Since its first publication in 1980, the Model has been updated previously in 2001, 2011, and 2017.