Maria Carolina of Austria (Maria Carolina Louise Josepha Johanna Antonia; 13 August 1752 – 8 September 1814) was Queen of Naples and Sicily as the wife of King Ferdinand IV and III, who later became King of the Two Sicilies. As de facto ruler of her husband's kingdoms, Maria Carolina oversaw the promulgation of many reforms, including the revocation of the ban on Freemasonry, the enlargement of the navy under her favorite, Sir John Acton, and the expulsion of Spanish influence. She was a proponent of enlightened absolutism until the advent of the French Revolution, when, in order to prevent its ideas gaining currency, she made Naples a police state.

Born an archduchess of Austria, the thirteenth child of Empress Maria Theresa and Holy Roman Emperor Francis I, Maria Carolina married Ferdinand as part of an Austrian alliance with Spain, of which Ferdinand's father was king. Following the birth of a male heir in 1775, Maria Carolina was admitted to the Privy Council. She dominated the Council until 1812, when she was sent back to Vienna. Like her mother, Maria Carolina arranged politically advantageous marriages for her children. Maria Carolina promoted Naples as a centre of the arts, patronising painters Jacob Philipp Hackert and Angelica Kauffman, and academics Gaetano Filangieri, Domenico Cirillo and Giuseppe Maria Galanti.

Maria Carolina, abhorring how the French treated their queen, her sister Marie Antoinette, allied Naples with Britain and Austria during the Napoleonic and French Revolutionary Wars. As a result of a failed Neapolitan invasion of French-occupied Rome, she fled to Sicily with her husband in December 1798. One month later, the Parthenopean Republic was declared, which repudiated Bourbon rule in Naples for six months. Deposed as Queen of Naples for a second time by French forces, in 1806, Maria Carolina died in Vienna in 1814, a year before her husband's restoration to Naples.

Maria Carolina was the last surviving child of Maria Theresa. She was also the last queen of Naples and Sicily before the unification of the two into the Kingdom of the Two Sicilies.

Born on 13 August 1752 at the Schönbrunn Palace in Vienna, Maria Carolina Louise Josepha Johanna Antonia was the thirteenth and sixth surviving child of Maria Theresa, Queen of Hungary and Bohemia and ruler of the Habsburg dominions, and Francis I, Holy Roman Emperor. She was a namesake of her elder sisters – Maria Carolina, who died two weeks after her first birthday, and Maria Carolina, who died several hours after being baptised – but she was known as Charlotte by her family. Her godparents were King Louis XV of France and his wife, Maria Leszczyńska. Maria Carolina was the daughter who resembled her mother most, inheriting her strong-willed and dominant personality.^{[citation needed]}

Maria Carolina formed a very close bond with her youngest sister, Maria Antonia. From very early on they shared the same governess, Countess Lerchenfeld. A testament to their closeness is the fact that when one caught an illness the other did too. In August 1767 Maria Theresa separated the two girls, hitherto raised together under the auspices of Countess Marie von Brandis, because of their bad behaviour. Soon after in October of the same year, Maria Carolina's sister Maria Josepha, destined to marry Ferdinand IV of Naples as part of an alliance with Spain, died during a smallpox epidemic before she could leave for Naples to marry him. Just five years earlier, Maria Josepha's older sister, Maria Johanna was previously engaged to the young king, but she too had died from smallpox. Anxious to save the Austro-Spanish alliance, Charles III of Spain, father of Ferdinand IV, requested one of Maria Josepha's sisters as a replacement. The empress offered the court of Madrid, negotiating on behalf of that of Naples, Maria Amalia or Maria Carolina. Because Maria Amalia was five years older than his son, Charles III opted for the latter. Maria Carolina reacted badly to her engagement, crying, entreating and saying that Neapolitan marriages were unlucky, considering that two of her sisters had died before they could marry Ferdinand. Her objections, however, did not delay her preparation for her new role as Queen of Naples by the Countess of Lerchenfeld. Nine months later, on 7 April 1768, Maria Carolina married Ferdinand IV of Naples by proxy, her brother Ferdinand representing the bride-groom.

The fifteen-year-old Queen of Naples journeyed at leisure from Vienna to Naples, making stops at Mantua, Bologna, Florence, and Rome on the way. She entered the Kingdom of Naples on 12 May 1768, disembarking at Terracina, where she took leave of her native attendants. From Terracina, she and her remaining suite, comprising her brother, the Grand Duke of Tuscany, and his wife Maria Luisa of Spain, ventured to Poztella, where she met her husband, whom she found "very ugly". To the Countess of Lerchenfeld, she wrote, "I love him only out of duty..." Ferdinand was not taken with her either, declaring, after their first night together, "She sleeps like the dead and sweats like a pig."

Maria Carolina's dislike of her husband, however, did not get in the way of her bearing children, as her most important wifely duty was to perpetuate the dynasty. In total, Maria Carolina bore Ferdinand eighteen children within twenty-one years, from 1772 to 1793. Seven of these children survived into adulthood including his successor, Francis I, the last Holy Roman Empress, a Grand Duchess of Tuscany, the last Queen of the French, and a Princess of Asturias. ^{[citation needed]}