| Millennium: | 1st millennium BC |
|---|---|
| Centuries: | 3rd century BC – 2nd century BC – 1st century BC |
| Decades: | 130s BC 120s BC 110s BC – 100s BC – 90s BC 80s BC 70s BC |
| Years: | 106 BC 105 BC 104 BC – 103 BC – 102 BC 101 BC 100 BC |
| 103 BC by topic | |
| Politics | |
| State leaders – Sovereign states | |
| Birth and death categories | |
| Births – Deaths | |
| Establishments and disestablishments categories | |
| Establishments – Disestablishments | |
| Gregorian calendar | 103 BC |
| Ab urbe condita | 651 |
| Armenian calendar | N/A |
| Assyrian calendar | 4648 |
| Bahá'í calendar | -1946–-1945 |
| Bengali calendar | -695 |
| Berber calendar | 848 |
| English Regnal year | N/A |
| Buddhist calendar | 442 |
| Burmese calendar | -740 |
| Byzantine calendar | 5406–5407 |
| Chinese calendar | 丁丑年 (2534/2594) — to —
戊寅年(2535/2595) |
| Coptic calendar | -386–-385 |
| Ethiopian calendar | -110–-109 |
| Hebrew calendar | 3658–3659 |
| Hindu calendars | |
| - Vikram Samvat | -46–-45 |
| - Shaka Samvat | N/A |
| - Kali Yuga | 2999–3000 |
| Holocene calendar | 9898 |
| Iranian calendar | 724 BP – 723 BP |
| Islamic calendar | 746 BH – 745 BH |
| Japanese calendar | |
| Korean calendar | 2231 |
| Minguo calendar | 2014 before ROC 民前2014年 |
| Thai solar calendar | 441 |
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.