Year 371 (CCCLXXI) was a common year starting on Saturday of the Julian calendar. At the time, it was known as the Year of the Consulship of Augustus and Petronius (or, less frequently, year 1124 Ab urbe condita). The denomination 371 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 fortified cities of the Danube, with Sirmium (Pannonia) at the forefront, contribute to stop an invasion of the Quadi.

• The Persian Empire attains the zenith of its power under King Shapur II as the Romans renew their war against Persia. Hostilities will continue for the next 5 years.

• Baekje forces sack the city of P'yongyang in Goguryeo.
• Sosurim becomes king of Goguryeo.^[1]

• Roman poet Ausonius writes of a voyage on the Rhine and the Moselle in his work 'Mosella'.

• Augustine of Hippo, age 17, travels to Carthage to continue his education in rhetoric.
• Martin of Tours becomes bishop of Tours (approximate date).

• Dao Wu Di, Chinese emperor of Northern Wei (d. 409)
• Sengrui, Chinese Buddhist monk and scholar (d. 438)
• Valentinian II, Roman consul and emperor (d. 392)

• April 12 – Zeno of Verona, Christian bishop and martyr
• August 1 – Eusebius of Vercelli, Christian bishop (b. 283)
• Gogugwon, king of Goguryeo (Korea)^[1]
• Hilarion, Syrian anchorite and saint (b. 291)
• Lucifer Calaritanus, Christian bishop (approximate date)