|Millennium:||1st millennium BC|
|Centuries:||3rd century BC – 2nd century BC – 1st century BC|
|Decades:||150s BC 140s BC 130s BC – 120s BC – 110s BC 100s BC 90s BC|
|Years:||128 BC 127 BC 126 BC – 125 BC – 124 BC 123 BC 122 BC|
|125 BC by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishments and disestablishments categories|
|Establishments – Disestablishments|
|Gregorian calendar||125 BC
|Ab urbe condita||629|
|English Regnal year||N/A|
— to —丙辰年
|- Vikram Samvat||-68–-67|
|- Shaka Samvat||N/A|
|- Kali Yuga||2977–2978|
|- Ǹrí Ìgbò||-1124–-1123|
|Iranian calendar||746 BP – 745 BP|
|Islamic calendar||769 BH – 768 BH|
|Juche calendar||N/A (before 1912)|
|Minguo calendar||2036 before ROC
|Thai solar calendar||419|
Year 125 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Hypsaeus and Flaccus (or, less frequently, year 629 Ab urbe condita). The denomination 125 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.
- Cleopatra Thea succeeds to the rule of the Seleucid Empire on the death of Seleucus V. She appoints Antiochus VIII Grypus as co-ruler.
- In Rome, Marcus Fulvius Flaccus proposes the extension of Roman citizenship to the northern Italians, but the Senate reacts by sending him off to deal with disturbances around Massilia. And in so doing commenced the conquest of Transalpine Gaul.
- Salisbury, Joyce (2001). Encyclopedia of Women in the Ancient World. ABC-CLIO. p. 56.