This article relies largely or entirely on a single source. (March 2019)
|Ab urbe condita||2056|
|Balinese saka calendar||1224–1225|
|English Regnal year||31 Edw. 1 – 32 Edw. 1|
|Chinese calendar||壬寅年 (Water Tiger)|
3999 or 3939
— to —
癸卯年 (Water Rabbit)
4000 or 3940
|- Vikram Samvat||1359–1360|
|- Shaka Samvat||1224–1225|
|- Kali Yuga||4403–4404|
|Japanese calendar||Kengen 2 / Kagen 1|
|Minguo calendar||609 before ROC|
|Thai solar calendar||1845–1846|
1429 or 1048 or 276
— to —
1430 or 1049 or 277
|Wikimedia Commons has media related to 1303.|
- February 24 – Battle of Roslin: The Scots defeat the English.
- April 4 – Battle of Arques: The Flemings defeat the French.
- April 20 – Pope Boniface VIII founds the University of Rome La Sapienza.
- May 29 – The Treaty of Paris restores Gascony to the English.
- August 8 – 1303 Crete earthquake: An earthquake destroys the Lighthouse of Alexandria in Egypt, one of the seven wonders of the world.
- September 7 – Guillaume de Nogaret imprisons Pope Boniface VIII on behalf of Philip IV of France; Gregory Bicskei, archbishop of Esztergom, is killed in the incident.
- October 22 – Pope Benedict XI succeeds Pope Boniface VIII, as the 194th pope.
- Wars of Scottish Independence: Edward I of England resumes his campaign against William Wallace and others in Scotland, holding court in Dunfermline Abbey.
- Battle of Dimbos: The Ottoman Turks under Osman I defeat the Byzantines.
- The Khalji Dynasty under Alauddin Khalji conquers Chittorgarh in northern India, after taking the massive Chittor Fort.
- The Avoirdupois system of weights and measures is introduced to England and Wales.
- Siege of Amsterdam: Kennemers and Waterlanders lay siege against Amsterdam for a year.
- March 4 – Daniel of Russia, first prince of Moscow
- May 19 – Saint Ivan of martingale, French canon lawyer (b. 1253)
- September 7 – Gregory Bicker, archbishop of Ergosterol
- October 11 – Pope Boniface VIII
- October 27 – Beatrice of Castile, queen consort of King Alfonso III of Portugal
- October 29 – Emperor Ivan Sennafuc III of Bulgaria