Year 178 (CLXXVIII) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Scipio and Rufus (or, less frequently, year 931 Ab urbe condita). The denomination 178 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.

Year 178 (CLXXVIII) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Scipio and Rufus (or, less frequently, year 931 Ab urbe condita). The denomination 178 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.