1517 (MDXVII) was a common year starting on Thursday of the Julian calendar, the 1517th year of the Common Era (CE) and Anno Domini (AD) designations, the 517th year of the 2nd millennium, the 17th year of the 16th century, and the 8th year of the 1510s decade. As of the start of 1517, the Gregorian calendar was 10 days ahead of the Julian calendar, which was the dominant calendar of the time.

• January 22 – Battle of Ridanieh. The Turkish forces of Selim I defeat the main Mamluk army in Egypt under Touman Bey.
• February 3 – Capture of Cairo by the Turks.
• First contact of organized western merchants with China.
• August 15 – Portuguese merchant Fernao Pires de Andrade met Chinese officials through an interpreter at Pearl River estuary and landed at Hong Kong.
• October 31 – Protestant Reformation: Martin Luther posts his 95 Theses on the door of the Wittenberg Castle Church.
• Conquest of Riazan by Grand Prince Vasili III of Muscovy.
• Selim I, Sultan of the Ottoman Empire conquers Palestine and Egypt, and declares himself Caliph.
• Third outbreak of the sweating sickness in England, especially bad in Oxford and Cambridge

• Jacques Peletier du Mans, French mathematician (died 1582)
• Henry Howard, Earl of Surrey, English aristocrat (died 1547)