The Protocol on Ireland/Northern Ireland sets outs arrangements the UK and the EU have agreed "to address the unique circumstances on the island of Ireland, to maintain the necessary conditions for continued North-South cooperation, to avoid a hard border and to protect the 1998 Agreement in all its dimensions". The Protocol itself is a relatively short document with provisions governing rights of indviduals, the Common Travel Area, customs and the movement of goods between the Northern Ireland and the rest of the UK and the EU, VAT and excise, state aid, the single electricity market, state aid, and 'other' areas of North-South cooperation on the island of Ireland. It also contains provisions regarding the institutional arrangements for managing the Protocol's implementation, safeguard clauses, and the democratic consent. The text was amended as part of the Windsor Framework in 2023.

The provisions of EU law made applicable by the Protocol in the UK with respect to Northern Ireland are contained in a series of annexes. Where the UK and the EU agree that a new EU act should be applied, the relevant act is added to the Annex by a Decision of the Joint Committee which has general responsibility for decision-making concerning the implementation of the Protocol. How the Protocol is implemented is also determined by UK legislation.