India–Iran relations are the bilateral relations between India and Iran. Independent India and Iran established diplomatic relations on 15 March 1950. During much of the Cold War period, relations between the Republic of India and the erstwhile Imperial State of Iran suffered due to different political interests—non-aligned India fostered strong military links with the Soviet Union while Iran enjoyed close ties with the United States. Following the 1979 revolution, relations between Iran and India strengthened momentarily. However, Iran's continued support for Pakistan and India's close relations with Iraq during the Iran–Iraq War impeded further development of Indo–Iranian ties. In the 1990s, India and Iran supported the Northern Alliance in Afghanistan against the Taliban regime. They continue to collaborate in supporting the broad-based anti-Taliban government led by Hamid Karzai and backed by the United States. The two countries signed a defense cooperation agreement in December 2002.
Even though the two countries share some common strategic interests, India and Iran differ significantly on key foreign policy issues. India has expressed strong opposition against Iran's nuclear programme and whilst both the nations continue to oppose the Taliban, India supports the presence of NATO forces in Afghanistan unlike Iran. Lucknow in Uttar Pradesh, India, continues to be a major centre of Shia culture and Persian study in South Asia. Iran is the second largest supplier of crude oil to India, supplying more than 425,000 barrels of oil per day, and consequently India is one of the largest foreign investors in Iran's oil and gas industry.
In 2011, the US$12 billion annual oil trade between India and Iran was halted due to extensive economic sanctions against Iran, forcing the Indian oil ministry to pay off the debt through a banking system through Turkey.
According to a BBC World Service Poll conducted at the end of 2005, 71% of Iranians viewed India's influence positively, with 21% viewing it negatively, the most favorable rating of India for any country in the world.
There are about 8,000 Iranian students studying in India. India provides 67 scholarships every year to Iranian students under ITEC, ICCR, Colombo Plan and IOR-ARC schemes. every year around 40,000 Iranians visit India for various purposes. 
 India and Iran have friendly relations in many areas, despite India not welcoming the 1979 Revolution. There are significant trade ties, particularly in crude oil imports into India and diesel exports to Iran. Iran frequently objected to Pakistan's attempts to draft anti-India resolutions at international organisations such as the OIC and the Human Rights Commission. India welcomed Iran's inclusion as an observer state in the SAARC regional organisation.
A growing number of Iranian students are enrolled at universities in India, most notably in Pune and Bangalore. The clerical government in Tehran sees itself as a leader of Shiites worldwide including India. Indian Shiites enjoy state support such as a recognised national holiday for Muharram. Lucknow continues to be a major centre of Shiite culture and Persian study in the subcontinent.
In the 1990s, India and Iran supported the Northern Alliance in Afghanistan against the Taliban regime. They continue to collaborate in supporting the broad-based anti-Taliban government led by Hamid Karzai and backed by the United States. The two countries signed a defense cooperation agreement in December 2002.
In August 2013, while carrying oil in the Persian Gulf, Iran detained India’s largest ocean liner Shipping Corporation (SCI)’s vessel MT Desh Shanti carrying crude from Iraq . But, Iran stood firm in its stand that the detention of the oil tanker was “purely a technical and non political issue”.
Oil and gas
In 2008–09, Iranian oil accounted for nearly 16.5% of India's crude oil imports. Indian oil imports from Iran increased by 9.5% in 2008–09 due to which Iran emerged as India's second largest oil supplier. About 40% of the refined oil consumed by India is imported from Iran. In June 2009, Indian oil companies announced their plan to invest US$5 billion in developing an Iranian gas field in the Persian Gulf. In September 2009, the Mehr news agency reported a Pakistani diplomat as saying "India definitely quitted the IPI (India-Pakistan-Iran) gas pipeline deal", in favour of Indo-US civilian nuclear agreement for energy security. Iranian officials however said India is yet to make an official declaration. In 2010, US officials warned New Delhi that Indian companies using the Asian Clearing Union for financial transactions with Iran run the risk of violating a recent US law that bans international firms from doing business with Iranian banks and Tehran's oil and gas sector, and that Indian companies dealing with Iran in this manner may be barred from the US. The United States criticises the ACU of being insufficiently transparent in its financial dealings with Iran and suspects that much of their assets are funnelled to blacklisted repressive organisations in Iran such as the Army of the Guardians of the Islamic Revolution. The United States Department of the Treasury also believes that Iran uses the ACU to bypass the US banking system. On 27 November 2010, the Indian government, through the Reserve Bank of India, instructed the country's lenders to stop processing current-account transactions with Iran using the Asian Clearing Union, and that further deals should be settled without ACU involvement. RBI also declared that they will not facilitate payments for Iranian crude imports as global pressure on Tehran grows over its nuclear programme. This move by the Indian government will make clear to Indian companies that working through the ACU "doesn't necessarily mean an Iranian counterpart has an international seal of approval". As of December 2010, neither Iran nor the ACU have responded to this development. India objected to further American sanctions on Iran in 2010. An Indian foreign policy strategist, Rajiv Sikri, dismissed the idea that a nuclear armed Iran was a threat to India, and said that India would continue to invest in Iran and do business. Despite increased pressure by the US and Europe, and a significant reduction in oil imports from Persian oil fields in 2012, leading political figures in India have clearly stated that they are not willing to stop trade relations altogether. To the contrary, they aim at expanding the commodity trade with the Islamic republic.
Renewed increase in oil imports
While overall, India’s total volume of imported crude has only been rising slightly from 3.2 million b/d in 2009-10 to 3.44 million b/d in 2012-13, imports from Iran have basically been fluctuating around 250,000 b/d from 2012 to 2013 and thus rising proportionally due to a halt for Iranian exports to Europe. The recent detainment of an Indian tanker by Iranian officials is unrelated to the oil embargo, but in an effort to save over USD 8.5 billion in hard currency, and realizing a 180-day waiver from US sanctions, India plans to increase Iranian imports by 11 million tons for 2014, in addition to the two million tons of crude oil shipped from Iran by June 2013, up 21.1% from last year.
India's nuclear vote with Iran
India, despite close relations and convergence of interests with Iran, voted against Iran in the International Atomic Energy Agency in 2005, which took Iran by surprise. A "welcoming prospect" Ali Larijani was reported as saying: "India was our friend". Stephen Rademaker also acknowledged that India's votes against Iran at the International Atomic Energy Agency were "coerced":
"The best illustration of this is the two votes India cast against Iran at the IAEA. I am the first person to admit that the votes were coerced."
The USA considers support from India – which is on 35-member board of Governors at the International Atomic Energy Agency – crucial in getting a sizeable majority for its proposal to refer the matter to the Security Council for positive punitive action against Iran. Greg Schulte, US ambassador to the IAEA, said "India's voice will carry particular weight...I hope India joins us in making clear our collective concerns about Iran's nuclear program". Schulte did not deny that the Indo-US nuclear deal was conditional to India supporting the US on the Iran issue. Appraising of the situation vis-a-vis Iran, a senior U.S. official told the New York Times that The Indians are emerging from their nonaligned status and becoming a global power, and they have to begin to think about their responsibilities. They have to make a basic choice..
The Bush administration, however, recognised India's close relations with Iran and tempered its position, stating that India can "go ahead with a pipeline deal involving Iran and Pakistan. Our beef with Iran is not the pipeline."
A highway between Zaranj and Delaram (Zaranj-Delaram Highway) is being built with financial support from India. The Chabahar port has also been jointly financed by Iran and India. India is helping develop the Chabahar Port, which will give it access to the oil and gas resources in Iran and the Central Asian states. By so doing, India hopes to compete with the Chinese, who are building Gwadar Port, in Pakistani Baluchistan.
Iran plans to use Chabahar for transshipment to Afghanistan and Central Asia, while keeping the port of Bandar Abbas as a major hub mainly for trade with Russia and Europe.
India, Iran and Afghanistan have signed an agreement to give Indian goods, heading for Central Asia and Afghanistan, preferential treatment and tariff reductions at Chabahar.
Work on the Chabahar-Milak-Zaranj-Dilaram route from Iran to Afghanistan is in progress. Iran is, with Indian aid, upgrading the Chabahar-Milak road and constructing a bridge on the route to Zaranj. India's BRO is laying the 213-kilometer Zaranj-Dilaram road. It is a part of India's USD 750 million aid package to Afghanistan.
The Chabahar port project is Iran's chance to end its US-sponsored economic isolation and benefit from the resurgent Indian economy. Along with Bandar Abbas, Chabahar is the Iranian entrepot on the North-South corridor. A strategic partnership between India, Iran and Russia is intended to establish a multi-modal transport link connecting Mumbai with St. Petersburg, providing Europe and the former Soviet republics of Central Asia access to Asia and vice versa.
India and Iran are discussing building a gas pipeline between the two countries along the bed of the Arabian Sea to bypass Pakistan, using the Chabahar port. Both the countries are pondering the delivery of natural gas produced in Turkmenistan with Indian assistance to north Iran while the Islamic Republic will send natural gas from its southern deposits to Indian consumers. This pipeline is conceived by India to replace the proposed Iran-Pakistan-India gas pipeline, the negotiations for which have dragged on due to the worsening of relations between India and Pakistan.
World's largest Zoroastrian population
The world's largest population of Zoroastrians are the Parsi community in India. When the Islamic Arabs invaded Persia, the local population which was unwilling to convert to Islam or accept dhimmi status were persecuted to different regions of the world with western India being the most significant. They sought refuge in the western coast of India, ever since then India turned into their home holding the highest numbers of Zoroastrians of the world. In the modern era, the Parsi community have contributed significantly to India and Pakistan in the areas of politics, industry, science, and culture. Prominent Indian Parsis include Dadabhai Naoroji (three times president of Indian National Congress), Field Marshal Sam Manekshaw, nuclear energy scientist Homi Bhabha, industrialist JRD Tata and the Tata family. The Queen rock star Freddie Mercury was an Indian Parsi born in Zanzibar. Zubin Mehta, a renowned conductor of Western classical music orchestras is also a Parsi originally from Mumbai.
- Foreign Relations of Iran
- Foreign relations of India
- Iran-Pakistan-India gas pipeline
- India-Israel relations
- Ibn Sina Academy of Medieval Medicine and Sciences
- Indo-Persian culture
- Hinduism in Iran
- Buddhism in Iran
- Zoroastrianism in India
- Irani (India)
- Nanda, Prakash. Rising India: Friends and Foes. Lancer Publishers, 2008. ISBN 9780979617416.
- Hunter, Shireen. Iran's foreign policy in the post-Soviet era: resisting the new international order. ABC-CLIO, 2010. ISBN 9780313381942.
- Zeb, Rizwan (12 February 2003). "The emerging Indo-Iranian strategic alliance and Pakistan". CACI Analyst. Retrieved 21 August 2013.
- "India's Iran calculus". Foreign Policy magazine. Retrieved 1 January 2011.
- Iran’s major oil customers, energy partners , Tehran Times
- Solomon, Jay; Sircar, Subhadip (29 December 2010). "India Joins U.S. Effort to Stifle Iran Trade". Wall Street Journal magazine. Retrieved 1 January 2011.
- India paid $5 bn Iran oil debt in full: central bank, AFP, 4 September 2011
- BBC World Service Poll GlobeScan
-  Retrieved 6 January2013
- Indian Council of World Affairs(ICWA): Iran-India Relations: Exploring Co-operation in Challenging Times Retrieved 6 August 2010
- Zeb, Rizwan (12 February 2003). "The emerging Indo-Iranian strategic alliance and Pakistan". CACI Analyst. Retrieved 21 August 2013.
- Aneja, Atul (August 15, 2013). "Iran detains Indian tanker carrying crude, wants undertaking". The Hindu (Chennai, India). Retrieved August 15, 2013.
- "Indian ship detention purely a technical issue: Iran". The Hindu (Chennai, India). 17 August 2013. Retrieved 18 August 2013.
- PressTV:$13bn: new record in Iran-India trade Retrieved 2 November 2008
-  Retrieved 14 August 2009
- India raises crude imports from Iran, Press TV, 7 May 2009
- India buys more Iran, less Saudi crude oil in '08/09, Reuters, 7 May 2009
- Does US road to better relations with Iran pass through India?, Christian Science Monitor, 18 July 2009
- OVL, IOC, OIL to invest $5bn in Iran gas field, Times of India, 25 June 2009
- "India has quit Iran gas pipeline deal: Report". The Times Of India. Archived from the original on 10 September 2009.
- "Energy Tribune". Energy Tribune. Retrieved 2012-09-08.
- Solomon, Jay; Sircar, Subhadip (29 December 2010). "India Joins U.S. Effort to Stifle Iran Trade". The Wall Street Journal.
- http://www.stockmarketsreview.com/reports/indian_stock_market_daily_morning_report_20101228_75028/. Missing or empty
- "RBI stifles Iran oil imports, says won’t clear payments". The Times of India.
- Corey Flintoff (22 July 2010). "In India, Few Takers For Tighter Iran Sanctions". npr. Retrieved 9 March 2011.
- S. Mehdudia (March 2013). "India not to halt imports from Iran". The Hindu
- Iran Oil Desk Rhodium Group. Retrieved November 6, 2013
- Iran oil imports to save India $8.5 bln Press TV-Text Only Version. Retrieved November 6, 2013
- "'India was our friend'". Rediff.com. Retrieved 2012-09-08.
- India's anti-Iran votes were coerced, says former US official
- Rajghatta, Chidanand (20 September 2005). "US-India nuclear deal under Iran gun". The Times Of India.
- Whitehouse archives
- Pajhwok Afghan News, 100-km road asphalted in Nimroz with Indian assistance
- India push for Iran's key port development Tehran Times – 6 July 2010
- Chopra, R.M. Indo-Iranian Cultural Relations through the Ages. published by Iran Society, Kolkata.
- Chopra, R.M. Indo-Iranian Cultural Relations in the 20th century. Indo-Iranica Vol.57 (1–4)
- Clawson, Patrick. (2005). Eternal Iran: Continuity and Chaos. ISBN 1-4039-6276-6. 2005. MacMillan.
- Multiple authors (2004). "India". Encyclopædia Iranica. (series of entries that cover Indian history and its relations with Iran)
- Keddie, Nikki; Matthee, Rudolph P. (ed.). (2002). Iran and the Surrounding World: Interactions in Culture and Cultural Politics. University of Washington Press. ISBN 0-295-98206-3.
- Tikku, G.L. (1971). Persian poetry in Kashmir 1339–1846. ISBN 0-520-09312-7
- Section on Persian literature in India: Rypka, January (1968). History of Iranian Literature. Reidel Publishing Company. OCLC 460598. ISBN 90-277-0143-1
- Chopra, R.M., "The Rise Growth And Decline of Indo-Persian Literature", 2012, published by Iran Culture House, New Delhi and Iran Society, Kolkata. 2nd Edition published in 2013.
- India-Iran Relations: A farewell to the gas pipeline?
- US concerns not to sway India-Iran relations
- India-Iran Relations Cannot Be Hostage To US
- India-Iran Relations: Key Security Implications