Year 1342 (MCCCXLII) was a common year starting on Tuesday and current year of the Julian calendar.

• January 21–June 27 – An-Nasir Ahmad, Sultan of Egypt, rules prior to being deposed by his half-brother As-Salih Ismail.
• May 7 – Pope Clement VI succeeds Pope Benedict XII, as the 198th Pope.
• July 16 – Louis I becomes king of Hungary.
• July 18 – Battle of Zava: Mu'izz al-Din Husayn defeats the Sarbadars.
• July 22 – St. Mary Magdalene's flood is the worst such event on record for central Europe.^[1]
• August 15 – Louis "the Child", age 4, succeeds his father, Peter II, as king of Sicily and duke of Athens; he is crowned on September 15 in Palermo Cathedral.
• September 4 – John III of Trebizond (John III Comnenus) becomes emperor of Trebizond.

• Guy de Lusignan becomes Constantine II, King of Armenia (Gosdantin, Կոստանդին Բ).
• The Greek Orthodox patriarch of Antioch is transferred to Damascus, under Ignatius II.
• Kitzbühel becomes part of Tyrol.
• Byzantine civil war of 1341–1347 – The Zealots seize power in Thessalonica, expelling its aristocrats and declaring themselves in favour of the regency.

• January 17 – Philip II, Duke of Burgundy (d. 1404)
• April 6 – Infanta Maria, Marchioness of Tortosa (d. after 1363)
• November 8 – Julian of Norwich, English mystic (approximate date; d. 1413)
• date unknown
  • Levon V Lusignan of Armenia (d. 1393)
  • Avignon Pope Clement VII (d. 1394)^[2]
  • Humphrey de Bohun, 7th Earl of Hereford (d. 1373)
  • John Trevisa, English translator (d. 1402)

• March 31 – Dionigi di Borgo San Sepolcro, Italian Augustinian friar
• April 25 – Pope Benedict XII^[3]
• July 16 – King Charles I of Hungary
• September 4 – Anna Anachoutlou, Empress of Trebizond
• November 29 – Michael of Cesena, Italian Franciscan leader (b. 1270)
• date unknown
  • Al-Jaldaki, Persian physician and alchemist
  • Peter Paludanus, French bishop and theologian (b. c. 1275)
  • William de Ros, 3rd Baron de Ros
• probable – Marsilius of Padua, Italian scholar (b. 1270)