The forecast for economic growth in Saudi Arabia has fallen further than in any other Middle East or North African state.
The IMF says the kingdom's economy will grow 4.3 per cent in 2009. In April, it forecast growth of 5.6 per cent.
"The effects of falling demand in advanced partner economies and increasing supply-side constraints in oil sectors are projected to be partly offset by robust domestic demand and activity in non-oil sectors," according to the World Economic Outlook.
The UAE's economy will grow by 6 per cent, down from 7 per cent in 2008. Kuwait will grow 5.8 per cent, compared with 5.9 per cent in 2008.
The IMF does not provide forecasts for Bahrain, Oman or Qatar.
Egypt's economic growth is expected to drop to 6 per cent from 7.2 per cent in 2008.
Iran's economy will grow by 5 per cent in 2009, compared with 5.5 per cent in 2008.