Foreign direct investment in Iran (FDI) has been hindered by unfavorable or complex operating requirements and by international sanctions, although in the early 2000s the Iranian government liberalized investment regulations. Iran ranks 62nd in the World Economic Forum's 2011 analysis of the global competitiveness of 142 countries. In 2010, Iran ranked sixth globally in attracting foreign investments.

Foreign investors have concentrated their activity in a few sectors of the economy: the oil and gas industries, vehicle manufacture, copper mining, petrochemicals, foods, and pharmaceuticals. Iran absorbed US$24.3 billion of foreign investment from 1993 to 2007 and US$34.6 billion for 485 projects from 1992 to 2009.

Opening Iran's market place to foreign investment could also be a boon to competitive multinational firms operating in a variety of manufacturing and service sectors, worth $600 billion to $800 billion in new investment opportunities over the next decade.

Firms from over 50 countries have invested in Iran in the past 16 years (1992–2008), with Asia and Europe receiving the largest share, as follows:

As of 2007, Asian entrepreneurs made the largest investments in the Islamic state by investing in 40 out of 80 projects funded by foreigners. The largest amount of foreign investment was in the industrial sector, including food and beverage, tobacco, textiles, clothing, leather, chemical, steel and oil derivates. The figure exceeded US$8.76 billion. Water, electricity and gas sector ranked second, attracting $874.83 million. In the third place, the real estate sector absorbed more than $406 million. Investments in service, telecommunication, transportation and mines reached $193 million, $14.3 million and $14.2 million respectively. Asian countries invested $7.666 billion in various projects followed by several multinational consortia. Investments by these multinational companies exceeded $1.39 billion (in four projects). Although European entrepreneurs were involved in 34 projects, they invested only in the range of $1.2 billion in the Islamic Republic. American countries also committed $12.329 million in the country; while investments by African states registered close to $4 million.

Stock of FDI in Iran equaled $16.82 billion (at home) and $2.075 billion (abroad) according to The World Factbook statistics in 2010.

According to the United Nations Conference on Trade and Development (UNCTAD), foreign direct investment (FDI) in Iran hit a new record in 2010 and surpassed 3.6 billion dollars despite sanctions imposed on the Islamic Republic. The EIU estimates that Iran's net FDI flow will rise by 100 per cent within the next four years (2010–14). The Economist estimates that FDI (net inflow) in Iran was $1.4 billion in 2011 (equivalent to 0.3% of GDP) down from $3.2 billion in 2010. The report forecasts this figure for 2012 to fall to $1.25 billion, but increase again for the next 3 years and to reach $1.8 billion in 2015. The Government of Iran says planned FDI in 2011 was $4.3 billion and planned FDI will reach $8–10 billion in 2012–13. However, UNCTAD later reported that FDI inflow in Iran was $3.05 billion in 2013, while Iran's FDI in other countries (i.e. outflow FDI) was $380 million.

Bushehr province and Khuzestan province enjoy the highest volume of foreign investment which mostly goes for oil and gas sectors. In 2012, the provinces of Fars, Gilan, Tehran, Kerman, Mazandaran and West Azerbaijan ranked first to sixth place in attracting foreign investment in the country.