The 1330s was a decade of the Julian Calendar which began on January 1, 1330, and ended on December 31, 1339.
- May 18 – Siege of Kamakura in Japan: Forces loyal to Emperor Go-Daigo, led by Nitta Yoshisada, enter and destroy the city, breaking the power of the Hōjō clan over the Kamakura shogunate. The Kamakura period ends, and the Kenmu Restoration under Go-Daigo begins.
- June 6 – William Donn de Burgh, 3rd Earl of Ulster, is murdered as part of the Burke Civil War in Ireland.
- June 8 – King Edward III of England seizes the Isle of Man from Scottish control.
- July 7 – The reign of Emperor Kōgon of Japan, first of the Northern Court (Ashikaga) Pretenders, ends.
- July 19 – Battle of Halidon Hill: Edward III of England decisively defeats Sir Archibald Douglas, during the last of the Wars of Scottish Independence. Berwick-upon-Tweed returns to English control.
- November 4 – The River Arno floods, causing massive damage in Florence, as recorded by Giovanni Villani.
- 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 famine in China, which has lasted since 1333 and killed 6,000,000, comes to an end.