Charles VI (October 1, 1685 – October 20, 1740) was Holy Roman Emperor from 1711 to 1740 and the second son of Leopold I with his third wife, Eleonore-Magdalena of Pfalz-Neuburg .

His educator was Anton Florian of Liechtenstein.

He was the contracted heir of the Spanish Habsburgs. When Charles II of Spain made Philip V his heir, Louis XIV violated the contract. The dispute for the crown of Spain led to the War of the Spanish Succession.

After his older brother Joseph I died suddenly, he had to return to Austria to take over the Emperor's throne. In 1711, he was made Holy Roman Emperor in Frankfurt.

Although Charles seems to have been clumsy in political affairs, the Austrian monarchy reached its widest expansion during his reign.

His children were Maria Theresia and Maria Anna, but he had no living male heirs. So he prepared the Pragmatic Sanction of 1713, which stated that his realm could not be divided and allowed that daughters also could inherit the throne from their fathers. When he died, the War of the Austrian Succession took place, but in the end the Pragmatic Sanction held up and his daughter succeeded him as Queen of Hungary and Bohemia and Archduchess of Austria. However, being a female, she was not elected Holy Roman Empress. Instead, Charles VII was elected. However, after Charles VII's reign, Maria Theresa's husband Joseph II was elected, ensuring that the Empire would continue in the Habsburg line.

Probably as a consequence of his years in Spain, he introduced the Spanish court ceremonial (Spanisches Hofzeremoniell) in Vienna and built the Spanish Riding School. Furthermore, the Reichskanzlei ("chancellory of the state") and the National Library were constructed during his reign and the Michaeler tract added to the Hofburg. Much was designed in baroque style in Vienna during Charles' reign.

He also had musical ambitions. Taught as a boy by Johann Joseph Fux, he composed, played the piano, and now and then conducted the court's band.

Names in other languages: German: Karl VI, Czech: Karel II., Hungarian: III. Károly, Slovak: Karol III, Latin: Carolus VI