The Windsor Framework is a post-Brexit legal agreement between the European Union and the United Kingdom which adjusts the operation of the Northern Ireland Protocol. The Framework was announced on 27 February 2023, formally adopted by both parties on 24 March 2023 and came into effect on 1 October 2023. The UK Government announced plans for revisions to the Framework's operation in January 2024.

The Framework was negotiated to address political concerns in the UK and especially among Ulster Unionists about the Northern Ireland Protocol. Under the terms of the Protocol, Northern Ireland, unlike the rest of the UK, remains in the EU single market for goods. This puts in place a de facto Irish Sea trade border for goods moving to Northern Ireland from Great Britain. The Framework changes aspects of the Protocol's operation, particularly to ease custom checks on goods arriving from Great Britain. It gives UK government more control over VAT rates applying in Northern Ireland and states that medicines placed on the market in Northern Ireland will be regulated by the UK and not the EU. It gives the Northern Ireland administration and UK government a mechanism to object to, pause, and potentially disapply updated and amended EU laws, mainly concerning goods.

Following the Framework's announcement, Ulster Unionist politicians, while stating that the Framework was an improvement on the original implementation of the Protocol, remained concerned that the nature of Northern Ireland's participation in the UK Internal Market was diminished by the Protocol's very existence. These concerns were a key factor in the refusal of the Democratic Unionist Party (DUP), from February 2022, to allow the operation of the Northern Ireland Assembly, thus suspending devolved government in Northern Ireland. In January 2024 the UK Government and DUP reached agreement on proposed revisions to the Framework's operation, the end of the DUP boycott, and thereby the restoration of devolved government.

The agreement relates to goods crossing the Irish Sea from Great Britain to Northern Ireland. It introduces "conceptual" green and red lanes to reduce checks and paperwork on goods that are destined for Northern Ireland, and separates them from goods at risk of moving into the EU Single Market. It also includes a number of agreements on medicine control, VAT and alcohol duty.

An element of the agreement that facilitates minimal checks on (mainly) food items being shipped from Great Britain, is the use of "not for EU" labels. This label indicates that the product is not certified to conform to EU standards and thus may not legally be sold (or resold) in the EU. The requirement for these labels was phased in over three years. "Meat and fresh dairy products are to be labelled from October 2023, all other dairy products from October 2024, and composite products, fruit, vegetables, and fish from July 2025". The Framework only requires these labels to be used on GB goods intended for sale in Northern Ireland, but the Government decided that they should be used in Great Britain too, beginning in October 2024. Following the change of government, the plan for UK-wide "not for EU" labelling was scrapped.

The framework introduces a mechanism called the "Stormont brake", which would allow the Northern Ireland Assembly to temporarily stop any changes to EU goods regulations from applying in Northern Ireland if the Assembly feared that the changes would have "significant and lasting effects on everyday lives".

According to the agreement, the Northern Ireland Assembly can trigger the brake on any new "significantly different" rule being implemented if 30 Members of the Legislative Assembly from two or more parties object, giving way to a 14-day consultation period before reference to the UK Government for consideration. Cross-community consent (support from both unionists and nationalists) is not required. However, "the government says a decision on whether to permanently block an EU rule, once suspended and following discussion in the Joint Committee, would not happen 'in the absence of a cross-community vote'".

As part of the Stormont brake, the Windsor Framework Democratic Scrutiny Committee was established.