A chronology of key events:
1902 - Ibn Saud takes control of Riyadh.
1912 - The Ikhwan (Brotherhood) is founded based on strict Wahhabi Sunni Islam, and provides key support for Ibn Saud.
1921-25 - After the collapse of the Ottoman Empire, Ibn Saud takes over Najd and Hijaz, the home to the Muslim holy cities of Mecca and Medina.
1928-30 - Ibn Saud defeats an Ikhwan uprising against his efforts to modernisation the region.
Saudi Arabia formed
1932 September - Ibn Saud unites his lands as the Kingdom of Saudi Arabia, and takes the King Abdulaziz.
1938 - Oil is discovered and production begins under the US-controlled Aramco (Arabian American Oil Company).
1953 November - King Abdulaziz dies and is succeeded by Crown Prince Saud, whose reign is marked by rivalry with Arab nationalist Egypt in the region and a power struggle with his borther Faisal at home.
1960 - Saudi Arabia is a founding member of Opec (Organisation of Petroleum Exporting Countries).
1964 November - King Saud is deposed by his brother Faisal.
1972 - Saudi Arabia gains control of 20% of Aramco, lessening US control over Saudi oil.
1973 - Saudi Arabia leads an oil boycott against the Western countries that supported Israel in the October Yom Kippur War with Egypt and Syria. Oil prices quadruple.
King Faisal assassinated
1975 March - King Faisal is assassinated by his nephew and succeeded by his brother Khalid.
1979 - Extremists seize the Grand Mosque of Mecca; the government regains control after 10 days and those captured are executed.
1980 - Saudi Arabia takes full control of Aramco from the US.
1981 May - Saudi Arabia is a founder member of the GCC (Gulf Cooperation Council).
King Khalid dies
1982 June - King Khalid dies of a heart attack and is succeeded by his brother, Crown Prince Fahd.
1986 November - King Fahd adds the title "Custodian of the Two Holy Mosques" to his name.
1987 - Saudi Arabia resumes diplomatic relations with Egypt, severed since 1979.
1990 - Saudi Arabia condemns Iraq's invasion of Kuwait and asks the US to intervene.
Saudi attacks Iraq
1991 - Saudi Arabia is involved in both air attacks on Iraq and the land force that went on to liberate Kuwait.
1992 March - King Fahd announces the "Basic System of Government" emphasising the duties and responsibilities of a ruler. He proposes setting up a Consultative Council (Majlis al-Shura).
1993 December - The Consultative Council is inaugurated. It is composed of a chairman and 60 members chosen by the king.
1994 - Islamic dissident Osama Bin Laden is stripped of his Saudi nationality.
1997 July - King Fahd increases the members of the Consultative Council from 60 to 90.
1999 October - Twenty Saudi women attend a session of the Consultative Council for the first time.
Relations with US
2001 11 September - 15 of the 19 hijackers involved in attacks on New York and Washington are Saudi nationals.
2001 December - Government issues ID cards to women for the first time.
2002 May - Revised criminal code includes ban on torture and right of suspects to legal representation, but violations continue.
Signs of dissent
2003 October - Police break up unprecedented rally in centre of Riyadh calling for political reform, a month after more than 300 Saudi intellectuals - women as well as men - sign a petition calling for change.
2003 November - King grants wider powers to Consultative Council, enabling it to propose legislation without his permission.
2004 February - Stampede at Hajj pilgrimage leaves 251 dead.
2004 - Sporadic attacks by the al-Qaeda jihadist group overthe previous two years acquire a systematic nature, including deadly assaults on the Yanbu petrochemical plant and the Khobar oil company, and the US consulate in Jeddah.
2005 February-April - First-ever nationwide municipal elections. Women do not take part in the poll.
2005 August - King Fahd dies, and is succeeded by Crown Prince Abdullah.
2005 November - World Trade Organization gives the green light to Saudi Arabia's membership following 12 years of talks.
2006 January - 363 Hajj pilgrims are killed in a crush during a stone-throwing ritual in Mecca. In a separate incident, more than 70 pilgrims are killed when a hostel in the city collapses.
2007 July - Religious police are banned from detaining suspects. The force has come under increasing criticism for overzealous behaviour after recent deaths in custody.
2008 July - British House of Lords reverses High Court decision and says their government acted lawfully in dropping investigation into the Al-Yamamah defence deal, as the Saudis had threatened to withdraw cooperation with London on security matters.
2008 December - Saudi Arabia and Qatar agree final delineation of border.
2009 February - King Abdullah sacks head of religious police, most senior judge and central bank head in rare government reshuffle. Also appoints country's first woman minister.
2009 July - A court issues verdicts in the first explicit terrorism trial for al-Qaeda militants in the country. Officials say 330 suspects were tried, but do not specify how many were found guilty. One is sentenced to death.
2010 October - US officials confirm plan to sell $60 billion worth of arms to Saudi Arabia - the most lucrative single arms deal in US history.
2011 February - King Abdullah announces increased welfare spending, as 'Arab Spring' unrest continues in the region.
2011 March - Saudi troops participate in crackdown on unrest in Bahrain.
2011 September - King Abdullah announces more rights for women, including the right to vote and run in municipal elections, and to be appointed to the consultative Shura Council.
A woman is sentenced to 10 lashes after being found guilty of driving, in the first legal punishment for violating the ban on women drivers. King Abdullah overturns the sentence.
2012 June - Saudi Arabia agrees to allow its women athletes to compete in the Olympics for the first time.
2013 February - King Abdullah swears in 30 women to the previously all-male Shura consultative council - the first time women have been able to hold any political office.
2014 September - Saudi Arabia and four other Arab states take part together with the United States in air strikes against Islamic State militant strongholds in Syria.
2015 January - King Salman ascends throne after King Abdullah dies.
2015 March - Saudi Arabia launches campaign of air strikes against Houthi rebels in Yemen.
2015 May - Two suicide bomb attacks on Shia mosques in Eastern Province kill at least 25 people, claimed by the Saudi branch of Islamic Group Sunni extremist group.
2015 September - Hundreds die in stampede near Mecca during annual Hajj pilgrimage, days after 109 people perished when a crane collapsed at the Grand Mosque, raising further concerns about safety standards during these mass events.
2015 November - Women stand in municipal elections for the first time, 20 are elected.
2016 January - Crowds in Tehran set Saudi embassy alight in protest at execution of Shia cleric Nimr al-Nimr, which also prompted Shia demonstrations in Iraq and Lebanon. Saudi Arabia breaks off diplomatic relations with Iran.
2016 April - Government approves a plan for far-reaching reforms to diversify the economy away from oil.
2016 June - A United Nations report accuses the Saudi-led coalition fighting Houthi rebels in Yemen of killing and injuring hundreds of children.
2017 February - The Saudi Stock Exchange and a major bank name women as their chief executives.
Rise of Prime Mohammed
2017 June - Saudi Arabia sparks a diplomatic crisis by leading an air, land and sea blockade by Arab countries, in an attempt to get Qatar to cut its alleged connections with terrorism and distance itself from Iran.
King Salman names his son Mohammed bin Salman first in line to the throne.
2017 September - Ban on women driving formally lifted.
2017 November - Purge of the kingdom's political and business leadership in move by Prince Mohammed to consolidate his power.
2018 April - Public cinema returns, almost 40 years after it was banned as un-Islamic.
2018 October - The killing of emigre reporter Jamal Khashoggi in the Saudi consulate in Istanbul causes an international outcry.
2019 September - Two major oil refineries damaged in air attacks, claimed by the Yemeni Houthi movement. Saudi Arabia, the US, Britain, France and Germany accuse Iran of responsibility.
2019 December - Five people are sentenced to death and three others jailed over the murder of Jamal Khashoggi, in a trial condemned by the UN special rapporteur as a cover-up.