|Millennium:||1st millennium BC|
|477 BC by topic|
|Gregorian calendar||477 BC|
|Ab urbe condita||277|
|Ancient Egypt era||XXVII dynasty, 49|
|- Pharaoh||Xerxes I of Persia, 9|
|Ancient Greek era||75th Olympiad, year 4|
|Balinese saka calendar||N/A|
|Chinese calendar||癸亥年 (Water Pig)|
2220 or 2160
— to —
甲子年 (Wood Rat)
2221 or 2161
|Coptic calendar||−760 – −759|
|Ethiopian calendar||−484 – −483|
|- Vikram Samvat||−420 – −419|
|- Shaka Samvat||N/A|
|- Kali Yuga||2624–2625|
|Iranian calendar||1098 BP – 1097 BP|
|Islamic calendar||1132 BH – 1131 BH|
|Minguo calendar||2388 before ROC|
|Thai solar calendar||66–67|
−350 or −731 or −1503
— to —
−349 or −730 or −1502
Year 477 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Pulvillus and Lanatus (or, less frequently, year 277 Ab urbe condita). The denomination 477 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 Spartan co-ruler Leotychides and the Athenian leader Themistocles lead a fleet and army to reoccupy northern Greece and to punish the aristocratic family of the Aleuads for having aided the Persians. Leotychides is caught accepting a bribe during the operations in Thessaly.
- Greek maritime cities around the Aegean Sea no longer wish to be under Spartan control and at Delos offer their allegiance, through Aristides, to Athens. They form the Delian League (also known as the Confederacy of Delos) with Cimon as their principal commander.
- Roman forces in a stronghold on the Cremera River are defeated by an army of Veientes from the Etruscan city of Veii in the Battle of the Cremera.
- Duke Dao of Qin, ruler of the state of Qin
- Emperor Itoku of Japan, according to legend.