Development planning started after the Second World War. Since then, a number of national development plans have been implemented by many developing countries, including Iran. Regional planning and regionalisation of developmental efforts have been major objective of all these plans. The aim of this paper is to scrutinise the status and nature of regional planning in the country’s development plans. It intends to see to what extent and how this objective has been achieved. By examining the development plans both in pre- and post-revolutionary periods, the paper concludes that despite strong policy pronouncements on regional development, regional planning has not yet become an integral part of Iran’s planning system, due mainly to the country’s centralised political and administrative structure, the built-in resistance of the bureaucracy to changes implied in the regionalisation policies, the sectoral structure of the country’s planning system, and regional inequality from the point of view of the executive authority, as well as excessive deprivation of some regions and their inability to mobilise local forces for development.