| Year | Date | Event |
| 585 BC | | Cyaxares dies and is succeeded by his son Astyages. |
| 580 BC | | Cyrus I dies and is succeeded by his son Cambyses I. |
| 559 BC | | Cambyses I dies and is succeeded by Cyrus the Great as king of Persia. |
| 550 BC | | The Achaemenid Empire is founded by Cyrus the Great after he overthrows and conquers the Median Empire. |
| 547 BC | | Cyrus conquers the Lydian Empire in western Asia Minor. |
| 545–540 BC | | Cyrus conquers Bactria, Arachosia, Sogdia, Sakastan, Chorasmia, and Margiana during his eastern campaign. |
| 539 BC | | Cyrus conquers the Neo-Babylonian Empire, frees thousands of slaves in Babylon and issues a declaration of human rights. This would later be inscribed into the Cyrus Cylinder. |
| 535 BC | | Cyrus commences the Achaemenid conquest of the Indus Valley. |
| 530 BC | | Cyrus dies, and is succeeded by his son Cambyses II. |
| 525 BC | | Cambyses II conquers Egypt after the Battle of Pelusium. Cyprus is also conquered by Cambyses. |
| 522 BC | | Cambyses dies and is succeeded by either his brother Bardiya or an impostor, Gaumata, pretending to be Bardiya. This individual dies months after becoming the King of Kings, and is succeeded by Darius the Great. Civil war breaks out as a result of the mysterious circumstances surrounding Darius' ascension, with Persis, Elam, Media, Assyria, Babylonia, Egypt, Parthia, Armenia, Margiana, Sattagydia, Sagartia, Hyrcania, and Scythia all revolting. Darius suppresses all the uprisings by 520 and restores order to the Achaemenid Empire. |
| 518 BC | | Darius completes the conquest of the Indus Valley. |
| 513 BC | | Darius expands the Achaemenid Empire into Europe, conquering European Scythia, Thrace, Paeonia, and the coastal Greek cities. |
| 512 BC | | Macedon submits to Persia. |
| Year | Date | Event |
| 620 | | Sasanian Empire reaches its greatest height, encompassing all of present-day Iran and Iraq and stretching from the eastern Mediterranean to Pakistan, and from parts of southern Arabia to the Caucasus and Central Asia. |
| 626 | June – July | Sasanian Empire lays siege to Constantinople, however is unable to capture it. |
| 628 | 25 February | Khosrow II is deposed and killed by his son Kavad II. |
| 628 | 6 September | Ardashir III becomes ruler of the Sasanian Empire. |
| 632 | 16 June | Yazdegerd III becomes ruler of the Sasanian Empire. |
| 633 | May | Battle of Ullais in which the Rashidun Caliphate defeats the Sasanian Empire resulting in the massacre of 70,000 Persians by Arabs. |
| 634 | October | Sasanian Empire led by Bahman Jaduya defeats the Rashidun Caliphate in the Battle of the Bridge. |
| 636 | | Arab invasion brings end of Sassanid dynasty and start of Islamic rule. |
| 636 | 16–19 November | Rashidun Caliphate defeats the Sasanian Empire in the Battle of al-Qadisiyyah, takes control of present-day Iraq. |
| 637 | | Destruction of the Ctesiphon library by Arabs of the Rashidun Caliphate. |
| 642 | | Rashidun Caliphate defeats the Sasanian Empire in the Battle of Nahavand, resulting in the near collapse of the Sasanian Empire. |
| 644 | 3 November | The second Rashidun caliph Umar ibn al-Khattab is assassinated by the Persian slave Abu Lu'lu'a Firuz. |
| 644 | 6 November | Uthman ibn Affan becomes the third Rashidun Caliph. During his reign, almost the whole of the former Sassanid empire's territories rebel from time to time, with major rebellions in Armenia, Azerbaijan, Fars, Sistan, Khorasan, and Makran. |
| 651 | | Rashidun Caliphate defeats the Sasanian Empire and the Göktürk Empire in the Battle of Oxus River. |
| 651 | | Yazdegerd III, the last Sassanid emperor, is killed near Merv putting an end to both his dynasty and to organized Persian resistance to Arab conquest. |
| Year | Date | Event |
| 1905 | December | The Persian Constitutional Revolution begins. |
| 1906 | | The first Persian Constitution was adopted during the Persian Constitutional Revolution. |
| 1911 | December | The Persian Constitutional Revolution ends; Russian troops enter Tabriz and force Shah to shut down Majles. |
| 1925 | | Reza Shah the Great overthrows the Qajar dynasty, becoming the first shah of the Pahlavi dynasty. |
| 1925 | 31 March | Solar Hijri calendar legally adopted in Iran. |
| 1941 | 25 August | Anglo-Soviet invasion of Iran: Three Soviet armies began invasion of Iran from the north, while British army invades Khuzestan and Central Iran. |
| 1945 | November | The Soviet Union established the Azerbaijan People's Government in Iranian Azerbaijan. |
| 1946 | 22 January | The Soviet-backed Kurdish Republic of Mahabad declared its independence from Iran. |
| 1946 | 2 March | Iran crisis: British troops withdrew from Iran. The Soviet Union violated its prior agreement and remained. |
| 1946 | 9 May | Iran crisis: The Soviet Union withdrew from Iran. |
| 1946 | 11 December | Iran regained control over the territory of the Azerbaijan People's Government. |
| 1946 | 15 December | Iran conquered Mahabad. |
| 1953 | August | Mohammad Mosaddegh is overthrown in a coup engineered by the British and American intelligence services. Fazlollah Zahedi is proclaimed as prime minister and the Shah returns. |
| 1979 | 11 February | Iranian revolution: The Iranian Monarchy collapsed in a popular revolution. |
| 1979 | 1 April | A referendum passed which made Iran an Islamic republic. |
| 1979 | 4 November | Iran hostage crisis |
| 1980 | 22 September | Iraq launched a full-scale invasion of Iran. The Iran–Iraq War would last until August 1988. The tactics used by both sides were similar to those used during World War I, including large-scale trench warfare with barbed wire stretched across trenches, manned machine-gun posts, bayonet charges, human wave attacks across a no-man's land, and extensive use of chemical weapons such as mustard gas by the Iraqi government against Iranian troops, civilians, and Iraqi Kurds. |
| 1981 | 9 October | Later Supreme Leader Ali Khamenei assumes office as the President of Iran under Supreme Leader Khomenei. |
| 1988 | 20 August | The Iran–Iraq War ends in a stalemate. The Iran–Iraq War was the deadliest conventional war ever fought between regular armies of developing countries. |
| 1988 | | Massacres of Iranian political prisoners, thousands of cases of forced disappearances, executions, torture and inhuman and degrading treatment. |
| 1989 | 3 June | 1st Supreme Leader of Iran and founder of the Islamic Republic, Ruhollah Khomeini, dies. |
| 1989 | 4 June | Ali Khamenei replaces Ruhollah Khomeini, becoming the second Supreme Leader of Iran. |
| 1989 | 28 July | A constitutional reform was allegedly approved by 97.6% of voters in a referendum, it was the first and so far only time the Constitution of the Islamic Republic of Iran has been amended. It made several significant changes to the system of government of the Islamic Republic such as eliminating the need for the Supreme Leader of the country to be a marja or chosen by popular acclaim. |
| 1989 | 16 August | Akbar Hashemi Rafsanjani becomes President of Iran, the first president to assume office under the post-reform constitution. |
| 1994 | 22 February | Homa Darabi an Iranian pediatrician and women's rights activist immolates herself in protest against compulsory hijab. |
| 1997 | 3 August | Mohammad Khatami replaces Rafsanjani as president. |
| Year | Date | Event |
| 2001 | 8 June | Iranian presidential election, 2001: President Mohammad Khatami was reelected with vast majority. |
| 2003 | December | 40,000 people are killed in an earthquake in southern Iran. |
| 2005 | 24 June | Iranian presidential election, 2005: Ahmadinejad defeated the more liberal Rafsanjani. |
| 2009 | 12 June | Iranian presidential election, 2009: Ahmadinejad re-elected for a second time after defeated Mousavi. |
| 2009 | 13 June | 2009–10 Iranian election protests: Protests in Iran over election results. |
| 2013 | 3 August | Hassan Rouhani replaces Ahmadinejad as president. |
| 2014 | | My Stealthy Freedom, an online movement in which women in Iran post photos of themselves without hijabs, as a protest against the compulsory hijab laws in the country. |
| 2015 | 14 July | Signing of Iran nuclear deal between Iran and the P5+1. |
| 2018 | 8 May | United States withdraws from the Iran nuclear deal |
| 2017–19 | | Iranian woman protest against compulsory hijab in multiple cities including Tehran, Kangavar, Isfahan and Shiraz. Many are physically assaulted with injuries including broken limbs and imprisoned. |
| 2019 | 9 September | Self immolation of women's rights activist Sahar Khodayari over six-month prison sentence for attempting to enter a public stadium to watch a football game, against the national ban against women at such events. Leads to widespread protests, and on 10 October 2019, more than 3,500 women attend the Azadi Stadium for a World Cup qualifier against Cambodia. |
| 2020 | 3 January | Quds Force commander Qasem Soleimani and commander of the Iran-backed Kata'ib Hezbollah militia, Abu Mahdi al-Muhandis, are assassinated in a U.S. drone strike in Baghdad. |
| 2021 | 3 August | Ebrahim Raisi replaces Rouhani as president. |
| 2022 | 16 September | 22-year-old Iranian woman Mahsa Amini, also known as Jina Amini, died in a hospital in Tehran, Iran, under suspicious circumstances, after her arrest by the Islamic Republic's Guidance Patrol. Eyewitnesses, including women who were detained with Amini, reported that she was severely beaten and that she died as a result of police brutality. Her death sparked widespread antigovernmental protests in Iran. |
| 2022–23 | | Civil unrest and protests against the Islamic Republic of Iran associated with the death in police custody of Mahsa Amini began on 16 September 2022 and lasted until 2023. |
| 2024 | 1 April | Israel bombed the Iranian embassy in Damascus, causing a brief escalation to direct conflict between two countries which lasted for 18 days. |
| 2024 | 19 May | Varzaqan helicopter crash and death of Iranian president, Ebrahim Raisi. |
| 2024 | 28 July | Masoud Pezeshkian appointed as the president of Iran. |
| 2024 | 31 July | Assassination of Ismail Haniyeh, Hamas political leader in Tehran, by an apparent Israel attack, increased tension between the two countries. |
| 2025 | 13 June | At approximately 4AM local time, Israel launched missiles into Iran, targeting their nuclear plants in an effort to prevent them from developing nuclear weapons. Iran's top military officials, Mohammad Hossein Bagheri and Hossein Salami, were killed in the conflict. |