|Millennium:||1st millennium BC|
|268 BC by topic|
|Gregorian calendar||268 BC|
|Ab urbe condita||486|
|Ancient Egypt era||XXXIII dynasty, 56|
|- Pharaoh||Ptolemy II Philadelphus, 16|
|Ancient Greek era||128th Olympiad (victor)¹|
|Balinese saka calendar||N/A|
|Chinese calendar||壬辰年 (Water Dragon)|
2429 or 2369
— to —
癸巳年 (Water Snake)
2430 or 2370
|Coptic calendar||−551 – −550|
|Ethiopian calendar||−275 – −274|
|- Vikram Samvat||−211 – −210|
|- Shaka Samvat||N/A|
|- Kali Yuga||2833–2834|
|Iranian calendar||889 BP – 888 BP|
|Islamic calendar||916 BH – 915 BH|
|Minguo calendar||2179 before ROC|
|Seleucid era||44/45 AG|
|Thai solar calendar||275–276|
−141 or −522 or −1294
— to —
−140 or −521 or −1293
Year 268 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Sophus and Russus (or, less frequently, year 486 Ab urbe condita). The denomination 268 BC 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.
- The Roman denarius coin is minted for the first time.
- The Romans found a colony at Malventum which they, for superstitious reasons, call Beneventum (since male means bad and bene means good in Latin).
- The Romans found a colony at Ariminum.
- Chremonides, an Athenian statesman and general, issues the Decree of Chremonides, creating an alliance between Sparta, Athens, and Ptolemy II of Egypt. The origins of this alliance lay in the continuing desire of many Greek states, notably Athens and Sparta, for a restoration of their former independence, along with the desire of Ptolemy II to create troubles for his rival Antigonus II, King of Macedonia. Ptolemy II's ambitions in the Aegean Sea are threatened by Antigonus Gonatas' fleet, so he carefully builds up a coalition of the rest of the Greeks against Macedonians. He especially cultivates Athens by supplying the city with grain.
- Ashoka becomes emperor of the Maurya Empire.
- Fu Sheng (Master Fu), Chinese Confusian scholar (d. 178 BC)
- Li Yiji, Chinese politician and adviser (d. 204 BC)