National Development Plan (NDP, Irish: Plean Forbartha Náisiúnta) is the title given by the Irish Government to a scheme of organised large-scale expenditure on (mainly) national infrastructure. The period covered by the seven year plan runs from 2000 to 2006. A second National Development Plan is currently in progress and is due to run until 2013 (spending €70 million a day every day from 2007 to 2013). The main elements to the original plan was the development of a national motorway network between the major cities in Ireland. The upgrading of the rail network was a secondary scheme.

By the start of 2009 substantial progress had been made on the motorway network, with all sections of the five major inter-urban motorways either under construction or complete. The M1 motorway from Dublin towards Belfast has been completed as far as the border with Northern Ireland. The last section of N1/M1 route to be completed was the motorway/dual carriageway upgrade that crossed the border to become an upgraded A1 route as far as Newry. This was the first cross-border road project and was opened to traffic on 2 August 2007, thus completing the N1/M1 route.

A development plan is an aspect of town and country planning in the United Kingdom comprising a set of documents that set out the local authority's policies and proposals for the development and use of land in their area. The development plan guides and informs day-to-day decisions as to whether or not planning permission should be granted, under the system known as development control. In order to ensure that these decisions are rational and consistent, they must be considered against the development plan adopted by the authority, after public consultation and having proper regard for other material factors.

Legislation (Section 54A of the Town and Country Planning Act 1990) requires that decisions made should be in accordance with the development plan unless material considerations indicate otherwise. Although development plans do not have to be rigidly adhered to, they provide a firm basis for rational and consistent planning decisions.

The development plan may contain a number of documents: Counties and most non-metropolitan unitary districts are covered by structure plans (in which the county, national park or unitary authority set out key strategic policies as a framework for local planning) and local plans (in which district councils and national park authorities set out more detailed policies to guide development in their areas, including proposals for specific sites). Structure plans may in some cases be prepared on a joint basis between two or more authorities (e.g. a county and a unitary authority or a national park).