|Centuries:||3rd century – 4th century – 5th century|
|Decades:||300s 310s 320s – 330s – 340s 350s 360s|
|Years:||335 336 337 – 338 – 339 340 341|
|338 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1091|
|Bahá'í calendar||−1506 – −1505|
|English Regnal year||N/A|
|Chinese calendar||丁酉年 (Fire Rooster)
3034 or 2974
— to —
戊戌年 (Earth Dog)
3035 or 2975
|- Vikram Samvat||394–395|
|- Shaka Samvat||260–261|
|- Kali Yuga||3439–3440|
|Igbo calendar||−662 – −661|
|Iranian calendar||284 BP – 283 BP|
|Islamic calendar||293 BH – 292 BH|
|Minguo calendar||1574 before ROC
|Thai solar calendar||881|
|Wikimedia Commons has media related to 338.|
Year 338 (CCCXXXVIII) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Ursus and Polemius (or, less frequently, year 1091 Ab urbe condita). The denomination 338 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 Romans, allied with the Goths, arrive in the north of the Roman Empire to protect the Danube frontier.
- Emperor Constantius II intervenes against the Persians in Armenia.
- Shapur II, king of the Persian Empire, begins a widespread persecution of Christians. Ordering forcible conversions to the state religion, Zoroastrianism, lest the Christians disrupt his realm while he is away fighting the Romans in Armenia and Mesopotamia.
- Eusebius of Nicomedia becomes Patriarch of Constantinople after Paul I is banished.
- Non-Christians are persecuted by the Roman Empire as pagans.
- Flavius Ablabius, Roman consul and politician
- Li Qi, emperor of the Ba-Di state Cheng Han (b. 314)
- Tuoba Yihuai, prince of the Tuoba Dai clan