This third edition of the United Nations Practical Manual on Transfer Pricing for Developing Countries (the Manual) is intended to draw upon the experience of the first edition (2013) and the second edition (2017) including feedback on the latter version, but it is also intended to reflect developments in the area of transfer pricing analysis and administration since that time. An important purpose of this Manual is to contribute to a common understanding of how the arm’s length principle is to be applied in order to avoid double taxation and prevent or resolve transfer pricing disputes, as highlighted in paragraph 4 of the Commentary on Article 9 of the UN Model Convention.