|Millennium:||1st millennium BC|
|Centuries:||5th century BC – 4th century BC – 3rd century BC|
|Decades:||330s BC 320s BC 310s BC – 300s BC – 290s BC 280s BC 270s BC|
|Years:||311 BC 310 BC 309 BC – 308 BC – 307 BC 306 BC 305 BC|
|308 BC by topic|
|Gregorian calendar||308 BC|
|Ab urbe condita||446|
|Bahá'í calendar||−2151 – −2150|
|English Regnal year||N/A|
|Chinese calendar||壬子年 (Water Rat)
2389 or 2329
— to —
癸丑年 (Water Ox)
2390 or 2330
|Coptic calendar||−591 – −590|
|Ethiopian calendar||−315 – −314|
|- Vikram Samvat||−251 – −250|
|- Shaka Samvat||N/A|
|- Kali Yuga||2794–2795|
|Igbo calendar||−1307 – −1306|
|Iranian calendar||929 BP – 928 BP|
|Islamic calendar||958 BH – 957 BH|
|Minguo calendar||2219 before ROC
|Thai solar calendar||236|
|Wikimedia Commons has media related to 308 BC.|
Year 308 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Mus and Rullianus (or, less frequently, year 446 Ab urbe condita). The denomination 308 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.
- Ptolemy crosses from Asia Minor into Greece, where he takes possession of Corinth, Sicyon and Megara.
- The Second Samnite War escalates when the tribes of the central Apennines, the Umbrians, Picentini, and Marsians join the war against Rome. However, Rome is able to control the uprising.
- The Etruscans sue for peace with Rome, which is granted by the Romans on severe terms.
- Cleopatra of Macedon, sister of Alexander the Great and daughter of King Philip II of Macedon and Olympias (b. c. 356 BC)