A chronology of key events:
1908 - King Carlos and eldest son assassinated in Lisbon. Second son Manuel becomes king.
1910 - King Manuel II abdicates amid revolution; Portugal proclaimed a republic.
1911 - New constitution separates church from state. Manuel Jose de Arriaga elected first president of republic.
1916-18 - Portugal fights World War I on Allied side.
1926 - Military coup. General Antonio de Fragoso Carmona becomes president.
1928 - Carmona appoints Antonio de Oliveira Salazar minister of finance.
1932 - Salazar becomes prime minister.
1933 - "New State" ("Estado Novo") constitution.
1936 - Salazar backs General Franco's nationalists in Spanish Civil War.
1939-45 - Portugal maintains official neutrality during World War II, but allows UK to use air bases in Azores.
1947 - Government crushes attempted revolt, deports labour leaders and army officers to Cape Verde Islands.
1949 - Portugal becomes founding member of Nato.
1955 - Portugal joins United Nations.
1955 - Indian opposition to Portuguese territory leads to severed diplomatic ties.
1958 - Admiral Americo Tomas appointed president.
1961 - India annexes Portuguese Goa. Rebellion breaks out in Angola, Guinea and Mozambique.
1968 - Salazar succeeded by Marcello Caetano.
1970 - Salazar dies.
1974 - Caetano government overthrown by group of army officers. General Antonio Ribeiro de Spinola becomes president, succeeded by General Francisco da Costa Gomes.
1974-75 - Independence for Portuguese colonies of Guinea-Bissau, Mozambique, Cape Verde Islands, Sao Tome and Principe, and Angola.
After more than 450 years in power, Portugal withdraws from Portuguese Timor - now East Timor - which is then occupied by Indonesia.
Huge influx of expatriates from former colonies.
1976 - Parliamentary elections. Mario Soares becomes prime minister. General Antonio Ramalho Eanes wins presidency.
1979 - Centre-right alliance wins elections.
1982 - Military Council of the Revolution abolished, civilian government formally restored.
1983 - Soares returns as prime minister.
1985 - Cavaco Silva becomes prime minister.
1986 January - Portugal becomes member of EEC (later EU).
Mario Soares elected president.
1987 - Cavaco Silva wins absolute majority in parliament.
1991 - Soares re-elected president.
1995 - Antonio Guterres becomes prime minister.
1996 - Jorge Sampaio elected president.
1999 - Last overseas territory, Macau, handed over to Chinese administration.
2001 - Jorge Sampaio elected for a second presidential term.
2001 December - Alqueva project on the Guadiana River nears completion as Europe's largest artificial lake, condemned by environmentalists as destructive, grandiose and unnecessary.
2001 December - Prime Minister Guterres resigns after his Socialist Party suffers unexpectedly heavy losses in local elections. Parliament is dissolved, early general election set for March 2002.
2002 January - Euro replaces the escudo.
2002 March - Social Democrat leader Jose Manuel Durao Barroso forms centre-right coalition after general election in which Socialists are defeated.
2003 August - Government declares a national calamity as forest fires sweep across vast areas of woodland. Officials say an area the size of Luxembourg has been lost to the fires. At least 18 people are killed; damage is estimated at one billion euros.
2004 July - Mr Barroso resigns as prime minister to become president of the European Commission. Pedro Santana Lopes, his successor as leader of Social Democratic Party, forms government.
2004 December - Four months into Prime Minister Lopes' government, President Sampaio calls early elections.
2005 February - Socialists sweep to victory in general elections. They usher in economic and social reforms which provoke a series of protest strikes among public sector workers.
2005 August - Portugal calls for outside help as deadly wildfires, exacerbated by drought and said to be the worst in recent times, rage across the country.
2006 January - Anibal Cavaco Silva, centre-right prime minister of 1985-1995, elected president.
2007 March - Mass demonstrations - the largest in recent years - against government's economic reforms.
2007 April - President endorses new law permitting abortion in first ten weeks of pregnancy, aligning Portugal with most other EU countries.
2007 July - Portugal takes over EU presidency.
2008 April - Portuguese parliament votes overwhelmingly in favour of ratifying EU's new treaty. European leaders had signed the treaty at a special summit in Lisbon in December 2007.
2008 May - Parliament votes to bring spelling of Portuguese language more in line with Brazilian practice. Opponents of the move say it is a capitulation to Brazilian influence.
2009 September - Governing Socialist Party wins re-election but loses its overall majority.
2009 October - Socialist Party leader Jose Socrates forms minority government.
2010 March - Tens of thousands of civil servants hold one-day strike in protest against plans to freeze public sector workers' pay.
Government announces package of austerity measures, including cuts in public spending and tax increases, to reduce Portugal's budget deficit.
2010 March-July - As eurozone debt crisis mounts, several leading credit rating agencies downgrade Portugal's government debt, further undermining confidence in the Portuguese economy.
2010 October - Portugal wins non-permanent seat on UN Security Council. Two-year term will begin on 1 January 2011.
2010 November - Parliament passes austerity budget aimed at bringing down high public debt levels.
2011 March - Government resigns after parliament rejects new austerity package. Jose Socrates continues as PM in caretaker capacity.
2011 April - Portugal becomes the third European Union country after Greece and Ireland to apply for EU financial assistance to help it cope with its budget deficit.
2011 May - The European Union and International Monetary Fund agree a 78bn-euro bailout for Portugal, on condition of sweeping spending cuts.
2011 June - Parliamentary elections. Ruling Socialist Party ousted. Winning Social Democratic Party forms governing coalition with the Popular Party.
2011 July - Credit ratings agency Moody's downgrades Portugal's public debt to junk status.
2011 August - The government announces the country's biggest spending cuts in 50 years, seeking to reduce public expenditure from 44.2% of GDP to 43.5% by 2015.
2011 October - The government submits another package of spending cuts and tax increases to parliament in an effort to meet the terms of the country's 78bn-euro bailout.
2011 November - Hundreds of thousands of workers go on strike a week before parliament is due to vote on the government's programme of spending cuts and tax rises.
Credit ratings agency Fitch downgrades Portugal's public debt to junk status.
2012 January - Credit ratings agency Standard and Poor's downgrades Portugal's rating to junk status.
The two largest unions, the CGTP and the UGT, split over a labour law reform proposed as part of Portugal's bailout, with the more moderate UGT reaching an agreement with the government.
2012 March - Public sector workers hold a 24-hour general strike in protest against the labour law reform and austerity measures.
2012 August - Figures show that Portugal's GDP shrank 1.2% in the second quarter.
2012 September - The EU, IMF and European Central Bank give Portugal another year to reduce its deficit below the EU target of 3% of GDP, after noting progress in rebalancing the economy.
2013 July - Several senior ministers resign over the handling of the economic crisis, but the government survives.
2013 November - The government approves more spending cuts, mainly affecting public-sector employees' wages, conditions and pensions, in order to avoid a second international bailout.
2014 May - Portugal exits international bailout without seeking back-up credit from its lenders.
2014 August - The government bails out the stricken lender Banco Espirito Santo - Portugal's largest private bank - to the tune of 3.9bn euros in order to avert a possible wider economic collapse.
2014 November - Interior Minister Miguel Macedo resigns in wake of corruption inquiry linked to allocation of fast-track residence permits, many of which have gone to foreigners willing to invest large sums in Portuguese property.
Former Socialist premier Jose Socrates is remanded in custody on suspicion of corruption, tax fraud and money laundering.
2015 January - The government approves rules allowing descendants of Jews who were expelled from the country centuries ago to claim Portuguese citizenship.
2015 March - The head of the tax collection authority resigns amid claims that he tried to shield the files of influential figures from scrutiny.
2015 November - Following inconclusive parliamentary elections, Socialist leader Antonio Costa forms centre-left government committed to relaxing some austerity measures.
2016 October - Former prime minister Antonio Guterres is appointed UN Secretary General.
2017 February - Portugal drops complaint to the EU over Spain's plan to build a nuclear waste storage facility which environmentalists fear could affect the River Tagus, which flows into Portugal. In return Spain agrees to share environmental information and organise consultations over the facility.