|Millennium:||1st millennium BC|
|Centuries:||6th century BC – 5th century BC – 4th century BC|
|Decades:||470s BC 460s BC 450s BC – 440s BC – 430s BC 420s BC 410s BC|
|Years:||443 BC 442 BC 441 BC – 440 BC – 439 BC 438 BC 437 BC|
|440 BC by topic|
|Gregorian calendar||440 BC|
|Ab urbe condita||314|
|Ancient Egypt era||XXVII dynasty, 86|
|- Pharaoh||Artaxerxes I of Persia, 26|
|Ancient Greek era||85th Olympiad (victor)¹|
|Chinese calendar||庚子年 (Metal Rat)
2257 or 2197
— to —
辛丑年 (Metal Ox)
2258 or 2198
|Coptic calendar||−723 – −722|
|Ethiopian calendar||−447 – −446|
|- Vikram Samvat||−383 – −382|
|- Shaka Samvat||N/A|
|- Kali Yuga||2662–2663|
|Iranian calendar||1061 BP – 1060 BP|
|Islamic calendar||1094 BH – 1093 BH|
|Minguo calendar||2351 before ROC
|Thai solar calendar||103–104|
|Wikimedia Commons has media related to 440 BC.|
Year 440 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Macerinus and Lanatus (or, less frequently, year 314 Ab urbe condita). The denomination 440 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.
- Samos, an autonomous member of the Delian League and one of Athens' principal allies with a substantial fleet of its own, quarrels with Miletus and appeals to Athens for assistance. Pericles decides in favour of Miletus, so Samos revolts. Pericles then sails to Samos with a fleet to overthrow its oligarchic government and install a democratic one. Sparta threatens to interfere. However, at a congress of the Peloponnesian League, its members vote not to intervene on behalf of Samos against Athens.
- Polykleitos completes one of his greatest statues, the Doryphorus (The Spear Bearer) (approximate date).
- The stela, Demeter, Persephone and Triptolemos, from Eleusis, is made (approximate date). It is now kept at the National Archaeological Museum of Athens.
- A temple for Poseidon is erected in Sounion.