|Millennium:||1st millennium BC|
|234 BC by topic|
|Gregorian calendar||234 BC
|Ab urbe condita||520|
|Ancient Egypt era||XXXIII dynasty, 90|
|- Pharaoh||Ptolemy III Euergetes, 13|
|Ancient Greek era||136th Olympiad, year 3|
|Chinese calendar||丙寅年 (Fire Tiger)
2463 or 2403
— to —
丁卯年 (Fire Rabbit)
2464 or 2404
|Coptic calendar||−517 – −516|
|Ethiopian calendar||−241 – −240|
|- Vikram Samvat||−177 – −176|
|- Shaka Samvat||N/A|
|- Kali Yuga||2867–2868|
|Iranian calendar||855 BP – 854 BP|
|Islamic calendar||881 BH – 880 BH|
|Minguo calendar||2145 before ROC
|Seleucid era||78/79 AG|
|Thai solar calendar||309–310|
Year 234 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Albinus and Ruga (or, less frequently, year 520 Ab urbe condita). The denomination 234 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 Epirote Alliance is replaced by the Epirote League, which is a federal state with its own parliament (or synedrion).
- The city of Pleuron is destroyed by Demetrius II.
- After the resignation of Lydiades, the city of Megalopolis joins the Achaean League.
- 100,000 Zhao soldiers are killed in the Battle of Pingyang.
- King Zheng begins the unification of China.
- Marcus Porcius Cato (Cato the Elder), Roman statesman, (d. 149 BC)
- Mete Khan, Xiongnu emperor, (d. 174 BC)
- Pharnavaz I of Iberia, King of Georgia
- Zenodotus of Ephesus, first librarian of the Library of Alexandria