1555 (MDLV) was a common year starting on Tuesday of the Julian calendar, the 1555th year of the Common Era (CE) and Anno Domini (AD) designations, the 555th year of the 2nd millennium, the 55th year of the 16th century, and the 6th year of the 1550s decade. As of the start of 1555, the Gregorian calendar was 10 days ahead of the Julian calendar, which was the dominant calendar of the time.

• Russia breaks 60 year old truce with Sweden by attacking Finland
• February 2 – Diet of Augsburg begins
• February 4 – John Rogers becomes first Protestant martyr in England
• February 9 – Bishop of Gloucester John Hooper is burned at the stake
• May 23 – Paul IV becomes Pope.
• September 25 – Peace of Augsburg is signed.