|Centuries:||6th century – 7th century – 8th century|
|Decades:||630s 640s 650s – 660s – 670s 680s 690s|
|Years:||662 663 664 – 665 – 666 667 668|
|665 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1418|
|Chinese calendar||甲子年 (Wood Rat)
3361 or 3301
— to —
乙丑年 (Wood Ox)
3362 or 3302
|- Vikram Samvat||721–722|
|- Shaka Samvat||587–588|
|- Kali Yuga||3766–3767|
|Minguo calendar||1247 before ROC
|Seleucid era||976/977 AG|
|Thai solar calendar||1207–1208|
Year 665 (DCLXV) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. The denomination 665 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.
- Kubrat, ruler (khagan) of Great Bulgaria, dies after a 33-year reign. He is succeeded by his son Batbayan who rules from Poltava (modern Ukraine) the lands north of the Black Sea and the Sea of Azov.
- Conflict between king Sighere of Essex and his brother Sæbbi by the struggle for overlordship between Mercia and Wessex.
- Muslim Conquest: An Arab army (40,000 men) advance through the desert and capture the Byzantine city of Barca (Libya).
- Wilfrid, Anglo-Saxon abbot, refuses to be consecrated in Northumbria as bishop and travels to Compiègne (France) to be consecrated by Agilbert, archbishop of Paris.
- Jaruman, bishop of Mercia, is despatched with Christian missionaries to reconvert Saxon tribes which have returned to paganism.
- According to the Annales Cambriae, the Anglo-Saxons convert to Christianity after the Second Battle of Badon.
- Sighere encourages his subjects to reject Christianity and return to their indigenous religion (approximate date).
- Féchín of Fore, Irish monk and saint
- April 16 – Fructuosus of Braga, French archbishop
- Hafsa bint Umar, wife of Muhammad
- Kubrat, ruler (khagan) of Great Bulgaria
- Li Zhong, prince of the Tang Dynasty (b. 643)
- Yu Zhining, chancellor of the Tang Dynasty (b. 588)
- Mayr-Harting, Henry (1991). The "Coming of Christianity to Anglo-Saxon England". Pennsylvania State University Press, p.129–147. ISBN 0-271-00769-9
- Mayr-Harting, Henry (1991). The "Coming of Christianity to Anglo-Saxon England". Pennsylvania State University Press, p. 117. ISBN 0-271-00769-9
- Thomas F. Glick, Steven Livesey, Faith Wallis, eds. (2014). Medieval Science, Technology, and Medicine: An Encyclopedia. Routledge. p. 464. ISBN 1135459398.