|Centuries:||7th century – 8th century – 9th century|
|Decades:||750s 760s 770s – 780s – 790s 800s 810s|
|Years:||786 787 788 – 789 – 790 791 792|
|789 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1542|
|Bahá'í calendar||−1055 – −1054|
|English Regnal year||N/A|
|Chinese calendar||戊辰年 (Earth Dragon)
3485 or 3425
— to —
己巳年 (Earth Snake)
3486 or 3426
|- Vikram Samvat||845–846|
|- Shaka Samvat||711–712|
|- Kali Yuga||3890–3891|
|Igbo calendar||−211 – −210|
|Japanese calendar||Enryaku 8
|Minguo calendar||1123 before ROC
|Thai solar calendar||1332|
|Wikimedia Commons has media related to 789.|
Year 789 (DCCLXXXIX) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar. The denomination 789 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.
- An uprising in Japan leads to a major defeat for Emperor Kammu, alongside a severe drought and famine.
- Fes, Morocco is founded by Idris I.
- Al-Khayzuran dies, leaving more of the effective power in the hands of Harun al-Rashid, the caliph of the Abbasid Caliphate.
- Caustantín becomes king of the Picts.
- Herford is founded by Charlemagne.
- The Admonitio Generalis is passed by Charlemagne.
- Eadburh marries Beorhtric of Wessex.
- The Anglo-Saxon Chronicle records the first appearance of Vikings in England.
- Ziryab, Arab poet and musician