1051 (MLI) was a common year starting on Tuesday of the Julian calendar, the 1051st year of the Common Era (CE) and Anno Domini (AD) designations, the 51st year of the 2nd millennium, the 51st year of the 11th century, and the 2nd year of the 1050s decade. As of the start of 1051, the Gregorian calendar was 6 days ahead of the Julian calendar, which was the dominant calendar of the time.

• Godwin, Earl of Wessex, is forced to leave England by King Edward the Confessor for refusing to take action against the townspeople of Dover. He returns the following year.
• Hilarion of Kiev becomes the first native metropolitan of the Eastern Orthodox Church in Kievan Rus.
• May 19 – Henry I of France marries Anne of Kiev at the cathedral of Reims.
• William of Normandy fights for his life and crown in Normandy.
• Heregeld is ended by King Edward the Confessor of England.

• Edgar Atheling, uncrowned King of England, 1066, after the Battle of Hastings
• Mi Fu, Chinese poet, painter, and calligrapher (d. 1107)

• January 22 – Ælfric Puttoc, archbishop of York
• Bi Sheng, Song Dynasty Chinese inventor of movable type printing