The 1220s was a decade of the Julian Calendar which began on January 1, 1220, and ended on December 31, 1229.
Significant people
- Abu Muhammad al-Wahid, Almohad Caliph of Morocco
- Abu Zakariya, first Sultan of the Hafsid Dynasty of Ifriqiya
- Adolf IV, Count of Schauenburg and Holstein
- Alfonso IX, King of León and Galicia
- Andrew II, King of Hungary and Croatia
- Baldwin II, Latin Emperor of Constantinople
- Konrad I, Duke of Masovia and Kujawy and High Duke of Poland
- Conrad IV, King of Jerusalem
- Chiconquiauhtzin, Tlatoani of Azcapotzalco
- Chūkyō, Emperor of Japan
- Dōgen, founder of the Sōtō school of Zen Buddhism in Japan
- Erik XI, King of Sweden
- Ferdinand III, King of Castile and Toledo
- Saint Francis of Assisi, Roman Catholic saint
- Frederick II, Holy Roman Emperor
- Genghis Khan, first Great Khan of the Mongol Empire
- Emperor Go-Horikawa of Japan
- Emperor Go-Toba of Japan
- Pope Gregory IX
- Henry III, King of England, Lord of Ireland, and Duke of Aquitaine
- Pope Honorius III
- Iltutmish, first Sultan of the Delhi Sultanate
- Jalal al-Din Mangburni, final Sultan of the Khwarazmian Empire
- James I, King of Aragon and Count of Barcelona
- Jochi, Mongol army commander and eldest son of Genghis Khan
- John of Brienne, King of Jerusalem and Latin Emperor of Constantinople
- John I, King of Sweden
- John III Doukas Vatatzes, Emperor of Nicaea
- Emperor Juntoku of Japan
- Al-Kamil, Ayyubid Sultan of Egypt
- Knut II, King of Sweden
- Leszek I the White, Duke of Sandomierz and High Duke of Poland
- Louis VIII, King of France
- Louis IX, King of France
- Lý Chiêu Hoàng, Empress of Vietnam
- Lý Huệ Tông, Emperor of Vietnam
- Manqu Qhapaq, first Emperor of the Inca Empire
- Ögedei Khan, second Great Khan of the Mongol Empire, third son of Genghis Khan
- Olaf the Black, King of the Isles
- Ottokar I, King of Bohemia
- Ramon Berenguer IV, Count of Provence and Count of Forcalquier
- Rǫgnvaldr Guðrøðarson, King of the Isles
- Rujing, Caodong Buddhist monk and Zen master
- Sancho II, King of Portugal
- Stephen Langton, Archbishop of Canterbury
- Subutai, Mongol commander and primary military strategist of the Mongol Empire
- Sukaphaa, first King of Ahom
- Theodore Komnenos Doukas, Despot of Epirus and Emperor of Thessalonika
- Tolui, Mongol commander and regent of the Mongol Empire, fourth son of Genghis Khan
- Trần Thái Tông, Emperor of Vietnam
- Trần Thủ Độ, military commander and regent of the Empire of Vietnam
- Valdemar II, King of Denmark
- Yuri II, Grand Prince of Vladimir
- Yaroslav, Prince of Novgorod
- Yusuf II al-Mustansir, Almohad Caliph of Morocco