|Millennium:||1st millennium BC|
|Centuries:||4th century BC – 3rd century BC – 2nd century BC|
|Decades:||280s BC 270s BC 260s BC – 250s BC – 240s BC 230s BC 220s BC|
|Years:||261 BC 260 BC 259 BC – 258 BC – 257 BC 256 BC 255 BC|
|258 BC by topic|
|Gregorian calendar||258 BC|
|Ab urbe condita||496|
|Ancient Egypt era||XXXIII dynasty, 66|
|- Pharaoh||Ptolemy II Philadelphus, 26|
|Ancient Greek era||130th Olympiad, year 3|
|Chinese calendar||壬寅年 (Water Tiger)
2439 or 2379
— to —
癸卯年 (Water Rabbit)
2440 or 2380
|Coptic calendar||−541 – −540|
|Ethiopian calendar||−265 – −264|
|- Vikram Samvat||−201 – −200|
|- Shaka Samvat||N/A|
|- Kali Yuga||2844–2845|
|Iranian calendar||879 BP – 878 BP|
|Islamic calendar||906 BH – 905 BH|
|Minguo calendar||2169 before ROC
|Seleucid era||54/55 AG|
|Thai solar calendar||285–286|
|Wikimedia Commons has media related to 258 BC.|
Year 258 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Calatinus and Peterculus (or, less frequently, year 496 Ab urbe condita). The denomination 258 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 Romans are able to regain the initiative in Sicily against Carthage by retaking Enna and Camarina. In central Sicily, they take the town of Mytistraton, which they have attacked twice previously. The Romans also move in the north by marching across the northern coast toward Panormus, but are not able to take the city.
- Gaius Duilius Nepos, the Roman commander who has won a major naval victory over the Carthaginians is made censor with Lucius Cornelius Scipio. The election of a novus homo (i.e. the first in his family to serve in the Roman Senate or be elected as consul) to the censorship is a very rare honor.
- Ptolemy II loses control of the territory of Cyrenaica.
- Erasistratus of Ceos founds a medical school at Alexandria.
- The forces of the Macedonian King Antigonus II and the Seleucid King Antiochus II win a naval victory at Cos against their common enemy, Ptolemy II. This victory secures Antigonus control over the Aegean Sea and the League of the Islanders. It also diminishes Ptolemaic naval power.
- According to legend, the Hồng Bàng Dynasty comes to an end.