Year 129 (CXXIX) was a common year starting on Friday of the Julian calendar. At the time, it was known as the Year of the Consulship of Celsus and Marcellus (or, less frequently, year 882 Ab urbe condita). The denomination 129 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.

• A defense for Numidia is constructed at Lambaesis by Legio III Augusta.
• Emperor Hadrian continues his voyages, now inspecting Caria, Cappadocia and Syria.

• The song "Angel's Hymn" is made.^[1]

• Change of Patriarch of Constantinople, from Patriarch Diogenes to Eleutherius.

• Chen Ji, Chinese official, chancellor (d. 199)
• Galen, Greek physician, anatomist (d. c. 200/216)
• Liu Hong, Chinese official, astronomer (d. 210)

• June 19 – Justus of Alexandria, Egyptian patriarch
• King Osroes I of the Parthian Empire