1542 (MDXLII) was a common year starting on Sunday of the Julian calendar, the 1542nd year of the Common Era (CE) and Anno Domini (AD) designations, the 542nd year of the 2ndmillennium, the 42nd year of the 16thcentury, and the 3rd year of the 1540s decade. As of the start of 1542, the Gregorian calendar was 10 days ahead of the Julian calendar, which was the dominant calendar of the time.

• December 14 – Accession of Mary, Queen of Scots

• June 6 – Richard Grenville, Elizabethan sailor (died 1591)
• June 24 – St. John of the Cross, Spanish Carmelite friar and poet (died 1591)
• October 15 – Akbar, Jellaladin Mahommed, ruler of the Mughal Empire (died 1605)
• December 8 – Mary, Queen of Scots (died 1587)
• Robert Bellarmine, Catholic theologian and saint (died 1621)
• Toda Kazuaki, samurai in the service of Tokugawa Ieyasu (died 1604)
• Anthony Shirley, English traveller (died 1635)
• John Speed, historian (died 1629)
• Horio Yoshiharu, Japanese daimyo (died 1611)
• Kuki Yoshitaka, Japanese naval commander
• Jan Zamoyski, Polish nobleman (died 1605)

• February 13 – Katherine Howard, Queen of England
• December 14 – James V, King of Scotland