Year 126 (CXXVI) was a common year starting on Monday of the Julian calendar. At the time, it was known as the Year of the Consulship of Verus and Ambibulus (or, less frequently, year 879 Ab urbe condita). The denomination 126 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.

• The old Pantheon is demolished by Emperor Hadrian, and the construction of a new one begins (its date is uncertain, because Hadrian chooses not to inscribe the temple).

• First year of the Yongjian era of the Chinese Han dynasty.

• August 1 – Pertinax, Roman emperor (d. 193)^[1]
• Lu Kang, Chinese politician and prefect (d. 195)

• Domitia Longina, Roman empress (b. c. 53 AD)
• Yan Ji (or Ansi), Chinese empress