Year 1337 (MCCCXXXVII) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar.

• March 16 – Edward, the Black Prince establishes the Duchy of Cornwall, becoming the first English Duke.^[1]
• May 24 – Philip VI of France confiscates Gascony from English control.^[2]
• August – Second War of Scottish Independence: English forces relieve Stirling Castle, ending Edward III of England's last campaign in Scotland.^[2]
• October – Hundred Years' War: Edward III of England formally rejects Philip VI's claim to the French throne, initiating hostilities between France and England.^[2][3]
• November – Battle of Cadzand: English troops raid the Flemish island of Cadzand.

• Bisham Priory is founded in England.
• The Scaligeri Family loses control of Padua; Alberto della Scala, patron of the music of the Trecento, moves to Verona.
• Petrarch, "father" of Renaissance humanism, first visits Rome to wander its mysterious ruins, with an eye for aesthetics as well as for history, exciting a renewed interest in Classical civilisation.
• The Sofia Psalter is produced in Bulgaria.
• The Despotate of Epirus is conquered by the Byzantine Empire.
• The famine in China, w.hich had lasted since 1332 and killed 6,000,000, comes to an end.
• Siege of Nicomedia: After its foundation by Osman I in about 1299, the Ottoman Empire expanded across Bithynia in north-west Anatolia by capturing territory from the Byzantine Empire.

• February 25 – Wenceslaus I, Duke of Luxembourg, Czech Duke of Luxembourg (d. 1383)
• date unknown
  • Louis II, Duke of Bourbon (d. 1410)
  • Jean Froissart, historian and courtier from Hainaut (d. 1405)
  • Bianca of Savoy, lady consort of Milan (d. 1387)
  • Chŏng Mong-ju, Goryeo diplomat and poet (d. 1392)
  • Robert III of Scotland, second monarch from the House of Stewart to rule Scotland (d. 1406)

• January 8 – Giotto di Bondone, Italian painter (b. 1267)
• June 7 – William I, Count of Hainaut (b. 1286)
• June 15 – Angelo da Clareno, Italian Franciscan and leader of a group of Fraticelli (b. 1247)
• June 25 – Frederick III of Sicily (b. 1272)
• June 30 – Eleanor de Clare, politically active English noble (b. 1290)
• date unknown
  • Changshi, khan of the Chagatai Khanate
  • William Frangipani, Latin Archbishop of Patras
  • Musa I of Mali, ruler of the Malian Empire (b. c.1280)
  • Prince Narinaga, Japanese Shōgun (b. 1326, d. either 1337 or 1344, the sources are contradictory)