| Millennium: | 1st millennium BC |
|---|---|
| Centuries: | |
| Decades: | |
| Years: |
| 121 BC by topic |
| Politics |
|---|
| Categories |
| Gregorian calendar | 121 BC CXXI BC |
| Ab urbe condita | 633 |
| Ancient Egypt era | XXXIII dynasty, 203 |
| - Pharaoh | Ptolemy VIII Physcon, 25 |
| Ancient Greek era | 164th Olympiad, year 4 |
| Assyrian calendar | 4630 |
| Balinese saka calendar | N/A |
| Bengali calendar | −713 |
| Berber calendar | 830 |
| Buddhist calendar | 424 |
| Burmese calendar | −758 |
| Byzantine calendar | 5388–5389 |
| Chinese calendar | 己未年 (Earth Goat) 2577 or 2370 — to — 庚申年 (Metal Monkey) 2578 or 2371 |
| Coptic calendar | −404 – −403 |
| Discordian calendar | 1046 |
| Ethiopian calendar | −128 – −127 |
| Hebrew calendar | 3640–3641 |
| Hindu calendars | |
| - Vikram Samvat | −64 – −63 |
| - Shaka Samvat | N/A |
| - Kali Yuga | 2980–2981 |
| Holocene calendar | 9880 |
| Iranian calendar | 742 BP – 741 BP |
| Islamic calendar | 765 BH – 764 BH |
| Javanese calendar | N/A |
| Julian calendar | N/A |
| Korean calendar | 2213 |
| Minguo calendar | 2032 before ROC 民前2032年 |
| Nanakshahi calendar | −1588 |
| Seleucid era | 191/192 AG |
| Thai solar calendar | 422–423 |
| Tibetan calendar | 阴土羊年 (female Earth-Goat) 6 or −375 or −1147 — to — 阳金猴年 (male Iron-Monkey) 7 or −374 or −1146 |
Year 121 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Opimius and Allobrogicus (or, less frequently, year 633 Ab urbe condita) and the Second Year of Yuanshou. The denomination 121 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.