1073 (MLXXIII) was a common year starting on Tuesday of the Julian calendar, the 1073rd year of the Common Era (CE) and Anno Domini (AD) designations, the 73rd year of the 2nd millennium, the 73rd year of the 11th century, and the 4th year of the 1070s decade. As of the start of 1073, the Gregorian calendar was 6 days ahead of the Julian calendar, which was the dominant calendar of the time.

• April 22 – Pope Gregory VII (Cardinal Hildebrand) succeeds Pope Alexander II as the 155th pope.
• Emperor Shirakawa ascends the throne of Japan
• Rabbi Yitchaki Alfassi finishes writing the Rif, an important work of Jewish law.
• John IX bar Shushan ends term as Syrian Patriarch of Antioch
• Beginning of Sviatoslav II's reign as ruler of Kievan Rus
• Seljuk Turks conquer Ankara

• David the Builder, King of Georgia
• Margrave Leopold III of Austria

• April 21 – Pope Alexander II
• June 15 – Emperor Go-Sanjō of Japan (b. 1034)
• Zhou Dunyi – Neo-Confucian philosopher in Song Dynasty China