|Centuries:||5th century – 6th century – 7th century|
|Decades:||530s 540s 550s – 560s – 570s 580s 590s|
|Years:||563 564 565 – 566 – 567 568 569|
|566 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1319|
|Chinese calendar||乙酉年 (Wood Rooster)
3262 or 3202
— to —
丙戌年 (Fire Dog)
3263 or 3203
|- Vikram Samvat||622–623|
|- Shaka Samvat||487–488|
|- Kali Yuga||3666–3667|
|Iranian calendar||56 BP – 55 BP|
|Islamic calendar||58 BH – 57 BH|
|Minguo calendar||1346 before ROC
|Seleucid era||877/878 AG|
|Thai solar calendar||1108–1109|
Year 566 (DLXVI) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. The denomination 566 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
- A Byzantine army under command of Baduarius assist the Gepids in their war against the Lombards. The Byzantines win the first battle in the lower Danube (Moesia), but the Gepid king Cunimund refuses to hand back the fortress city of Sirmium (modern Serbia) as he had promised.
- Emperor Justin II facing an empty treasury, breaks the treaty with the Gepids that exists since 565. King Alboin of the Lombards, makes an alliance with the Avars under Bayan I, at the expense of tough conditions. They demand a tenth of Lombards' cattle and half of the war booty.
- Justin II sends his cousin Justin to exile in Alexandria, where he is installed as Augustal prefect of Egypt. There he is murdered in his sleep, his head is cut off and brought to Constantinople. Probably by assignment of empress Sophia.
- Ainmuire mac Sétnai becomes High King of Ireland and rules from 566–569 (this according to the Book of Leinster).
- Fei Di, age 12, succeeds his father Wen Di as emperor of the Chinese Chen Dynasty. He honored his grandaunt Zhang Yao'er with the title of Grand Empress and she becomes his regent.
- Kirtivarman I succeeds his father Pulakeshin I as king of the Chalukya Dynasty (India). During his rule he completes the subjugation of the Kadambas and annexes the port of Goa.
- Abbas ibn Abd al-Muttalib, uncle of Muhammad (approximate date)
- Gao Zu, emperor of the Tang Dynasty (d. 635)
- Xiao, empress of the Sui Dynasty (approximate date)
- Yuchi Chifan, empress of Northern Zhou (d. 595)
- Domnall Ilchelgach, High King of Ireland
- Forggus mac Muirchertaig, High King
- Justin, Byzantine aristocrat and general
- Pulakeshin I, king of the Chalukya Dynasty (India)
- Wen Di, emperor of the Chen Dynasty (b. 522)
- Martindale, Jones & Morris (1992) p. 753–754
- Connor, Steve (2014-07-07). "Our explosive past is written in the Antarctic ice". i. London. p. 17.