November 1979 - US imposes the first sanctions after Iranian students stormed the US embassy and took diplomats hostage earlier in the year. Iranian products are banned from import into the United States apart from small gifts, information material, foodstuffs and some carpets. $12bn in Iranian assets are frozen.
March 1995 - President Bill Clinton issues executive orders preventing US companies from investing in Iranian oil and gas and trading with Iran.
May 1995 - Clinton bans US trade with and investment within Iran.
April 1996 - Congress passes a law requiring the US government impose sanctions on foreign firms investing more than $20m a year in Iran's energy sector.
December 2006 - After having called on Iran to halt its uranium enrichment programme in July, the UN Security Council imposes sanctions on Iran's trade in nuclear-related materials and technology and freezes the assets of individuals and companies involved with nuclear activities. The sanctions are mainly an effort to curtail Iran's growing nuclear capacity, but while programmes to enrich uranium were stopped in 2002, they restarted in late 2005.
March 2007 - UN Security Council votes to toughen sanctions by banning all of Iran’s arms exports and extending the freeze on assets of those associated with the enrichment programme. One month later, the EU publishes an expanded list of Iranian individuals and companies deemed persona non grata in the bloc.
October 2007 - The US announces a raft of new unilateral sanctions against Iran, the toughest since it first imposed sanctions almost 30 years ago, for "supporting terrorists". The sanctions cut more than 20 organisations associated to Iran’s Islamic Revolution Guard Corps from the US financial system and three state-owned banks.
March 2008 - UN Security Council passes further sanctions, including the monitoring of Iranian banks and all Iranian cargo planes and ships suspected of carrying previously sanctioned items. It also extends asset freezes.
June 2010 - UN Security Council imposes fourth round of sanctions against Iran over its nuclear programme, including tighter financial curbs and an expanded arms embargo. The measures prohibit Iran from buying heavy weapons such as attack helicopters and missiles.
US Congress imposes new unilateral sanctions targeting Iran’s energy and banking sectors. Penalties are instated for firms that supply Iran with refined petroleum products worth over a certain amount.
May 2011 - US blacklists the 21st Iranian state bank, the Bank of Industry and Mines, for transactions with previously banned institutions.
August 2010 - EU prohibits the creation of joint ventures with enterprises in Iran engaged in oil and natural gas industries, as well as the import and export of arms and equipment related to nuclear activities. The sale, supply, and transfer of equipment and technology used for natural gas production is also banned.
November 2011 - The US, UK and Canada announce bilateral sanctions on Iran. While the US expands sanctions to companies that aid Iran’s oil and petrochemical industrials, the UK mandates all British financial institutions stop doing business with Iranian counterparts.
January 2012 - US imposes sanctions on Iran's central bank, the main clearing-house for its oil export profits. Iranian in turn threatens close off the transport of oil through the Strait of Hormuz.
The European Union announces an oil embargo on Iran unless it curtails its nuclear programme.
June 2012 - US bans the world’s banks from completing oil transactions with Iran, and exempts seven major customers - India, South Korea, Malaysia, South Africa, Sri Lanka, Taiwan and Turkey - from economic sanctions in return for their cutting imports of Iranian oil.
July 2012 - EU ban of Iranian oil exports takes effect.
October 2012 - Iran's rial currency falls to a new record low against the US dollar, having lost about losing 80 per cent of its value since 2011, which many economists peg as the result of international sanctions.
EU tightens sanctions on the country’s banking, trade, and energy sectors. The package prohibits any transactions with Iranian banks and financial institutions and includes an embargo on Iranian natural gas.