1613 (MDCXIII) was a common year starting on Tuesday of the Gregorian calendar and a common year starting on Friday of the Julian calendar, the 1613th year of the Common Era (CE) and Anno Domini (AD) designations, the 613th year of the 2nd millennium, the 13th year of the 17th century, and the 4th year of the 1610s decade. As of the start of 1613, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1923.

• January – Galileo observes Neptune, but mistakes it for a star and so is not credited with its discovery.
• February 7 – An Assembly of the Russian Empire elects Mikhail Romanov to be Tsar of Russia, and establishes the Romanov Dynasty.
• June 29 – Fire destroys London's Globe Theatre
• Francesco Andreini's L'Adamo is published.
• King James I of England successfully mediates the Peace of Knäred treaty between Denmark and Sweden.
• The New River was opened, to supply London with drinking water from Hertfordshire
• Adriaen Block's ship Tyger is destroyed by fire, forcing him and his crew to spend the winter on Manhattan
• James I of England comdemns duels in his proclamation Against Private Challenges and Combats
• Ottoman Empire invades Hungary
• Locust swarm destroys La Camarque, France
• Sultan Agung takes the throne of the kingdom of Mataram on Java.
• December 6 death of Anton Praetorius