Austria's population stands at 9.1 million as of 2023, with approximately 1.95 million residing in Vienna. The country maintains one of Europe's lowest population densities at 109 people per square kilometer, concentrated primarily in the eastern lowlands and major alpine valleys. Ethnic Austrians comprise 80.8% of the population according to 2021 census data. Recognized minorities include Croats in Burgenland (16,000), Slovenes in Carinthia (13,000), Hungarians in Burgenland (9,000), Czechs in Vienna (8,000), Slovaks (4,000), and Roma (2,000). These figures represent Austrian citizens claiming minority status under the 1976 Ethnic Groups Act. The foreign-born population reached 2.3 million in 2023, with Germans forming the largest group at 238,000, followed by Serbians (122,000), Turks (119,000), and Romanians (133,000).
German serves as the official language, spoken by 97% of residents as either first or second language. Austrian German differs from standard German in vocabulary, pronunciation, and administrative terminology. Regionally distinct dialects include Viennese, Central Bavarian spoken in Salzburg and Upper Austria, and Alemannic in Vorarlberg. Croatian holds co-official status in Burgenland's Croat-majority communities, while Slovene maintains similar status in portions of Carinthia under the 1955 Austrian State Treaty. Carinthian Slovenes numbered approximately 13,000 in the 2001 census, concentrated in the Gail, Rose, and Jauntal valleys. Hungarian functions as a recognized minority language in three Burgenland municipalities. Turkish speakers number 263,000 as of 2021, representing children of guest workers recruited between 1964 and 1973.
Roman Catholicism claims 55.2% adherence according to 2021 data, down from 73.6% in 2001. The Austrian Bishops Conference reported 4.66 million registered members in 2022, representing active parish enrollment rather than cultural identification. Islam constitutes 8.3% of the population, primarily Sunni, with 700,000 adherents concentrated in Vienna, Linz, and Salzburg. The Islamic Religious Community received official recognition in 1912 under Austro-Hungarian law, making Austria the first Western European state to grant Islam legal status. Protestantism accounts for 3.4%, split between the Evangelical Church of the Augsburg Confession (Lutheran) at 2.8% and the Helvetic Confession (Reformed) at 0.6%. Eastern Orthodoxy represents 2.2%, predominantly Serbian and Romanian congregations. No religious affiliation reached 22.4% in 2021, concentrated among those under 40 in urban areas.
The Habsburg dynasty shaped Austrian identity from 1282 when Rudolf I secured the Duchy of Austria until the monarchy's dissolution in 1918. Frederick III became Holy Roman Emperor in 1452, establishing five centuries of Habsburg imperial rule. Maximilian I married Mary of Burgundy in 1477, acquiring the Low Countries and laying groundwork for Spanish inheritance through their son Philip. Charles V ruled Spain, the Netherlands, Austria, and German territories from 1519 to 1556 when he divided the empire, assigning Austrian lands to his brother Ferdinand I. The Ottoman siege of Vienna in 1529 failed after three weeks, but Turkish forces controlled Hungary until Eugene of Savoy defeated them at Zenta in 1697. The 1683 siege saw Kara Mustafa's 150,000 troops surround Vienna from July 14 until Polish King Jan III Sobieski relieved the city on September 12.
Maria Theresa ruled from 1740 to 1780, defending her succession against Prussia, Bavaria, Saxony, and France in the War of Austrian Succession. She instituted compulsory primary education in 1774 and centralized administration while maintaining the feudal system. Her son Joseph II abolished serfdom in 1781 through the Patent of Abolition, eliminated torture, and issued the 1781 Edict of Tolerance permitting Protestant and Orthodox worship. Napoleon defeated Austria at Austerlitz on December 2, 1805, forcing Francis II to dissolve the Holy Roman Empire on August 6, 1806, continuing as Emperor Francis I of Austria. The Congress of Vienna convened from September 1814 to June 1815, redrawing European borders under Austrian Foreign Minister Klemens von Metternich. Austria received Lombardy-Venetia, Salzburg, and Tyrol while losing the Austrian Netherlands.
Chancellor Metternich suppressed nationalist movements through censorship and police surveillance until the 1848 revolutions forced his resignation on March 13. Demonstrations in Vienna on March 13-15 killed approximately 50 protesters before Ferdinand I promised a constitution. Hungarian independence movements under Lajos Kossuth required Russian military intervention to suppress in August 1849. Franz Joseph I ascended December 2, 1848, ruling until his death November 21, 1916, the longest reign in Austrian history at 68 years. The 1867 Ausgleich created Austria-Hungary, granting Hungary equal status under the dual monarchy. Austria retained Cisleithania comprising present-day Austria, Czech Republic, Slovakia, Slovenia, and parts of Poland, Ukraine, and Italy, totaling 300,000 square kilometers with 28 million inhabitants.
Archduke Franz Ferdinand's assassination in Sarajevo on June 28, 1914, triggered Austria-Hungary's July 28 ultimatum to Serbia. World War I mobilized 7.8 million Austro-Hungarian troops, suffering 1.2 million deaths and 3.6 million wounded by November 1918. The empire dissolved between October 28 and November 12, 1918, as constituent nations declared independence. The Treaty of Saint-Germain-en-Laye signed September 10, 1919, reduced Austria to 83,879 square kilometers, 12% of the empire's former size, with 6.5 million inhabitants. Article 88 prohibited union with Germany without League of Nations consent. The Burgenland transferred from Hungary to Austria in 1921 following a plebiscite, adding 3,965 square kilometers.
The First Republic endured hyperinflation reaching 14,000% between 1921 and 1922 before League of Nations loans stabilized currency in August 1922. Political violence intensified between Socialist Schutzbund and conservative Heimwehr paramilitaries, culminating in July 15, 1927, when police killed 89 demonstrators protesting acquittal of right-wing militants who had murdered a socialist and child. Engelbert Dollfuss dissolved parliament on March 4, 1933, governing through emergency decrees. The February 12-16, 1934, civil war saw government forces bombard socialist housing complexes in Vienna, killing approximately 350 and wounding 1,000. Dollfuss banned the Nazi Party on June 19, 1933, but Austrian Nazis assassinated him July 25, 1934, during a failed coup attempt.
Kurt Schuschnigg succeeded Dollfuss, maintaining the authoritarian Fatherland Front government until German pressure forced his February 12, 1938, meeting with Hitler at Berchtesgaden. Hitler demanded Schuschnigg appoint Nazi sympathizer Arthur Seyss-Inquart as Interior Minister and lift the ban on Austrian Nazis. Schuschnigg announced a March 13 plebiscite on independence March 9, but Hitler issued an ultimatum March 11 demanding cancellation and Schuschnigg's resignation. German troops crossed the border March 12, 1938, encountering no resistance. The Anschluss referendum on April 10, 1938, reported 99.73% approval under Nazi supervision without secret ballots. Austria ceased to exist as Ostmark, divided into Reichsgaue administrative districts.