|Centuries:||2nd century – 3rd century – 4th century|
|Decades:||230s 240s 250s – 260s – 270s 280s 290s|
|Years:||265 266 267 – 268 – 269 270 271|
|268 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1021|
|Chinese calendar||丁亥年 (Fire Pig)
2964 or 2904
— to —
戊子年 (Earth Rat)
2965 or 2905
|Coptic calendar||−16 – −15|
|- Vikram Samvat||324–325|
|- Shaka Samvat||190–191|
|- Kali Yuga||3369–3370|
|Iranian calendar||354 BP – 353 BP|
|Islamic calendar||365 BH – 364 BH|
|Minguo calendar||1644 before ROC
|Seleucid era||579/580 AG|
|Thai solar calendar||810–811|
Year 268 (CCLXVIII) was a leap year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Paternus and Egnatius (or, less frequently, year 1021 Ab urbe condita). The denomination 268 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.
- September – Battle of Naissus: Emperor Gallienus, aided by Aurelian, defeats a Gothic coalition (50,000 warriors) near Naissus (Niš, modern Serbia).
- Gallienus is killed by his own senior officers at Mediolanum (Milan) while besieging his rival Aureolus, one of the Thirty Tyrants. Aureolus is murdered in turn by the Praetorian guard.
- Marcus Aurelius Claudius is charged by the Senate for having murdered Gallienus (it will never be proven). He becomes the new emperor of Rome and will reign as Claudius II.
- Claudius II asks the Senate to spare the lives of Gallienus's family and political supporters. Emperor Gallienus is deified and buried in a family tomb on the Appian Way.
- The Alamanni invade Italy north of the Po River.
- The Visigoths first appear as a distinct people.
- November – Battle of Lake Benacus: A Roman army (35,000 men) under emperor Claudius II defeats the Germanic tribes of the Alamanni along the banks of Lake Garda.
- Victorinus is declared emperor of the Gallic Empire by the legions at Augusta Treverorum (Trier), following the murders of his predecessors. He is recognized by the provinces of Gaul and Britain, but Hispania is reunited with the Roman Empire.
- Aureolus, Roman usurper
- Wang Yuanji, wife of Sima Zhao (b. 217)
- Gallienus, Roman emperor
- Laelianus, Roman usurper
- Marcus Aurelius Marius, Roman emperor (Gaul)
- Postumus, Roman emperor of the Gallic Empire
- December 26 – Pope Dionysius