|Millennium:||1st millennium BC|
|103 BC by topic|
Year 103 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Marius and Orestes (or, less frequently, year 651 Ab urbe condita). The denomination 103 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.
- Gaius Marius prepares a campaign against the Ambrones and Teutones under king Teutobod who are settled in Gaul.
- Tryphon and Athenion lead the Second Servile War in Sicily.
- Alexander Jannaeus succeeds his brother Aristobulus I as king and high priest of Judea, until 76 BC.
- Marcus Furius Bibaculus, Roman poet
- Aristobulus I, king of Judea.
- Gaius Lucilius, Roman satirist
- Khallata Naga of Anuradhapura, king of the Anuradhapura Kingdom