|Centuries:||3rd century – 4th century – 5th century|
|Decades:||300s 310s 320s – 330s – 340s 350s 360s|
|Years:||333 334 335 – 336 – 337 338 339|
|336 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1089|
|Chinese calendar||乙未年 (Wood Goat)
3032 or 2972
— to —
丙申年 (Fire Monkey)
3033 or 2973
|- Vikram Samvat||392–393|
|- Shaka Samvat||257–258|
|- Kali Yuga||3436–3437|
|Iranian calendar||286 BP – 285 BP|
|Islamic calendar||295 BH – 294 BH|
|Minguo calendar||1576 before ROC
|Seleucid era||647/648 AG|
|Thai solar calendar||878–879|
Year 336 (CCCXXXVI) was a leap 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 Nepotianus and Facundus (or, less frequently, year 1089 Ab urbe condita). The denomination 336 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 military successes of Emperor Constantine I result in most of Dacia being reconquered by the Roman Empire.
- The first recorded customs tariff is in use in Palmyra.
- January 18 – Pope Mark succeeds Pope Sylvester I as the 34th pope.
- Pope Mark begins to build the basilica of San Marco; the church is devoted to St. Mark.
- Arius, Alexandrian priest, collapses in the street at Constantinople (approximate date).
- Pope Mark dies at Rome after an 11-month reign. No successor is immediately found.
- Murong De, emperor of the Xianbei state Southern Yan (d. 405)
- Richū, emperor of Japan (approximate date)