| Millennium: | 1st millennium BC |
|---|---|
| Centuries: | 2nd century BC – 1st century BC – 1st century |
| Decades: | 100s BC 90s BC 80s BC – 70s BC – 60s BC 50s BC 40s BC |
| Years: | 81 BC 80 BC 79 BC – 78 BC – 77 BC 76 BC 75 BC |
| 78 BC by topic | |
| Politics | |
| State leaders – Sovereign states | |
| Birth and death categories | |
| Births – Deaths | |
| Establishments and disestablishments categories | |
| Establishments – Disestablishments | |
| Gregorian calendar | 78 BC |
| Ab urbe condita | 676 |
| Armenian calendar | N/A |
| Bahá'í calendar | -1921 – -1920 |
| Bengali calendar | -670 |
| Berber calendar | 873 |
| Buddhist calendar | 467 |
| Burmese calendar | -715 |
| Byzantine calendar | 5431 – 5432 |
| Chinese calendar | [[Sexagenary cycle|]]年 (2559/2619) — to —
[[Sexagenary cycle|]]年(2560/2620) |
| Coptic calendar | -361 – -360 |
| Ethiopian calendar | -85 – -84 |
| Hebrew calendar | 3683 – 3684 |
| Hindu calendars | |
| - Bikram Samwat | -21 – -20 |
| - Shaka Samvat | N/A |
| - Kali Yuga | 3024 – 3025 |
| Holocene calendar | 9923 |
| Iranian calendar | 699 BP – 698 BP |
| Islamic calendar | 720 BH – 719 BH |
| Japanese calendar | |
| Korean calendar | 2256 |
| Thai solar calendar | 466 |
Year 78 BC was a year of the pre-Julian calendar.