Year 175 (CLXXV) was a common year starting on Saturday of the Julian calendar. At the time, it was known as the Year of the Consulship of Piso and Iulianus (or, less frequently, year 928 Ab urbe condita). The denomination 175 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.

• Marcus Aurelius suppresses a revolt of Avidius Cassius, governor of Syria, after the latter proclaims himself emperor.
• Avidius Cassius fails in seeking support for his rebellion and is assassinated by Roman officers. They sent his head to Aurelius, who persuades the Senate to pardon Cassius's family.
• Commodus, son of Marcus Aurelius and his wife Faustina, is named Caesar.
• M. Sattonius Iucundus, decurio in Colonia Ulpia Traiana, restores the Thermae of Coriovallum (modern Heerlen^[1]). There are sources that state this happened in the 3rd century.^[2]

• Confucian scholars try to ensure their capacity in the royal court of China. They are massacred by the eunuchs.

• Ammonius Saccas, Egyptian philosopher (d. 242)
• Pope Pontian (approximate date) of the Catholic Church (d. 235)
• Sun Ce, Chinese general, warlord (d. 200)
• Yang Xiu, Chinese official, adviser (d. 219)
• Zhou Yu, Chinese general, strategist (d. 210)

• January 14 – Pontianus of Spoleto, Christian martyr (b. 156)
• Avidius Cassius, Roman general, usurper (b. AD 130)
• Concordius of Spoleto, Christian martyr (approximate date)
• Faustina the Younger, Roman empress (b. AD 130)
• Vettius Valens, Greek astrologer, writer (b. AD 120)