AD 78 (LXXVIII) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Novius and Commodus (or, less frequently, year 831 Ab urbe condita). The denomination AD 78 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.

This article relies largely or entirely on a single source. (October 2018)

• Liu Qing, Chinese prince of the Han Dynasty (d. 106)
• Wang Fu, Chinese historian, poet and philosopher (approximate date)
• Zhang Heng, Chinese mathematician, astronomer, inventor, and statesman (d. 139)

• Gaius Salonius Matidius Patruinus, Roman politician
• Vologases I, king of the Parthian Empire^[2]