|Millennium:||1st millennium BC|
|54 BC by topic|
|Gregorian calendar||54 BC
|Ab urbe condita||700|
|Ancient Egypt era||XXXIII dynasty, 270|
|- Pharaoh||Ptolemy XII Auletes, 27|
|Ancient Greek era||181st Olympiad, year 3|
|Chinese calendar||丙寅年 (Fire Tiger)
2643 or 2583
— to —
丁卯年 (Fire Rabbit)
2644 or 2584
|Coptic calendar||−337 – −336|
|Ethiopian calendar||−61 – −60|
|- Vikram Samvat||3–4|
|- Shaka Samvat||N/A|
|- Kali Yuga||3047–3048|
|Iranian calendar||675 BP – 674 BP|
|Islamic calendar||696 BH – 695 BH|
|Minguo calendar||1965 before ROC
|Seleucid era||258/259 AG|
|Thai solar calendar||489–490|
|Wikimedia Commons has media related to 54 BC.|
Year 54 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Appius and Ahenobarbus (or, less frequently, year 700 Ab urbe condita). The denomination 54 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: Appius Claudius Pulcher and Lucius Domitius Ahenobarbus.
- Gallic Wars:
- July – Second of Caesar's Invasions of Britain: receives nominal submission from the Tribal chief Cassivellaunus and installs Mandubracius as a friendly king.
- Winter – Ambiorix revolts in Gaul. He joins with Catuvolcus in an uprising against the Roman army. Caesar's senior officers Lucius Aurunculeius Cotta and Quintus Titurius Sabinus are ambushed by the Eburones, and killed with almost their entire force.
- Pompey builds the first permanent theatre in Rome.
- Crassus arrives in Syria as proconsul and invades Parthian Empire, initiating the Roman–Persian Wars, which were to last nearly seven centuries.
- Octavia Minor and Gaius Claudius Marcellus Minor married.
- The beginning of the breakup of the First Triumvirate with the death of Caesar's daughter Julia.
- Seneca the Elder (approximate date), Roman rhetor (d. c. 39 AD)
- Tibullus (approximate date), Roman poet (d. 19 BC)
- July 31 – Aurelia Cotta, mother of Julius Caesar (b. 120 BC)
- Gaius Valerius Catullus, Roman poet (b. 84 BC)
- Huo Chengjun, Empress of the Han Dynasty of China
- Julia, daughter of Julius Caesar, wife of Pompey (in childbirth) (b. 83 BC or 82 BC)
- Lucius Aurunculeius Cotta, Roman legate of Julius Caesar
- Lucius Valerius Flaccus, urban praetor
- Mithridates III, king of Parthia
- Quintus Titurius Sabinus, Roman legate of Julius Caesar