The 520s decade ran from January 1, 520, to December 31, 529.
Significant people
- Ahkal Mo' Nahb I, Ajaw (Lord) of Palenque (Mayan Empire)
- Boethius, philosopher
- Childebert I, Frankish king, 524-558
- Clodoald, saint
- Chlodomer, King of Orleans, 511-524
- Chlothar I, Frankish King
- Dionysius Exiguus, inventor of the Anno Domini
- Godomar, King of Burgundy
- Guntheuc, Queen of Orleans
- Justin I, Eastern Roman Emperor, 518-527
- Kaleb of Axum, King of Ethiopia
- Sigismund of Burgundy, King of the Burgundians, 516-524
- Theoderic the Great, King of the Ostrogoths, 475-526