|Millennium:||1st millennium BC|
|47 BC by topic|
|Gregorian calendar||47 BC|
|Ab urbe condita||707|
|Ancient Egypt era||XXXIII dynasty, 277|
|- Pharaoh||Cleopatra VII, 5|
|Ancient Greek era||183rd Olympiad, year 2|
|Balinese saka calendar||N/A|
|Chinese calendar||癸酉年 (Water Rooster)|
2650 or 2590
— to —
甲戌年 (Wood Dog)
2651 or 2591
|Coptic calendar||−330 – −329|
|Ethiopian calendar||−54 – −53|
|- Vikram Samvat||10–11|
|- Shaka Samvat||N/A|
|- Kali Yuga||3054–3055|
|Iranian calendar||668 BP – 667 BP|
|Islamic calendar||689 BH – 688 BH|
|Minguo calendar||1958 before ROC|
|Seleucid era||265/266 AG|
|Thai solar calendar||496–497|
80 or −301 or −1073
— to —
81 or −300 or −1072
Year 47 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Calenius and Vatinius (or, less frequently, year 707 Ab urbe condita). The denomination 47 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.
- Consuls: Quintus Fufius Calenus, Publius Vatinius.
- Civil War:
- January 13 – Pharaoh Cleopatra VII promotes her younger brother Ptolemy XIV of Egypt to co-ruler.
- February – Roman general Julius Caesar and his ally Cleopatra VII of Egypt defeat the forces of the rival Egyptian Queen Arsinoe IV in the Battle of the Nile. Ptolemy is killed; Caesar, with the aid of Mithridates I of the Bosporus, then relieves his besieged forces in Alexandria.
- September 2 – Pharaoh Cleopatra VII promotes her son Caesarion to co-ruler.
- August 2 – Caesar defeats Pharnaces II of Pontus, king of the Bosphorus, in the Battle of Zela (the war Caesar tersely describes as veni, vidi, vici).
- Battle at Mount Tabor in Judea: Roman troops, commanded by Gabinius, defeat the forces of Alexander, son of Aristobulus II of Judea, attempting to re-establish Judean independence. Some 10,000 Jews died at the hands of the Romans.
- June 23 – Prince Caesarion of Egypt, later Pharaoh Ptolemy XV (d. 30 BC)
- Marcus Antonius Antyllus, son of Mark Antony and Fulvia (d. 30 BC)
- Pharaoh Ptolemy XIII of Egypt (drowned in the Nile) (b. 62 or 61 BC)
- Pharnaces II of Pontus (b. c. 97 BC)