|Centuries:||7th century – 8th century – 9th century|
|Decades:||700s 710s 720s – 730s – 740s 750s 760s|
|Years:||728 729 730 – 731 – 732 733 734|
|731 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1484|
|Bahá'í calendar||-1113 – -1112|
|English Regnal year||N/A|
|Chinese calendar||庚午年 (Metal Horse)
3427 or 3367
— to —
辛未年 (Metal Goat)
3428 or 3368
|- Vikram Samvat||787–788|
|- Shaka Samvat||653–654|
|- Kali Yuga||3832–3833|
|Igbo calendar||-269 – -268|
|Japanese calendar||Tenpyō 3
|Minguo calendar||1181 before ROC
|Thai solar calendar||1274|
|Wikimedia Commons has media related to 731.|
Year 731 (DCCXXXI) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. The denomination 731 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.
- Battle of the Defile between the Umayyads and the Turgesh results in heavy casualties for the Umayyad army, halting Muslim expansion in Central Asia for almost two decades.
- Pope Gregory III elected by acclamation as the 90th pope during the funeral procession for Pope Gregory II; he is consecrated bishop a month later.
- Pope Gregory III condemns Iconoclasm.