|Centuries:||7th century – 8th century – 9th century|
|Decades:||710s 720s 730s – 740s – 750s 760s 770s|
|Years:||737 738 739 – 740 – 741 742 743|
|740 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1493|
|Bahá'í calendar||−1104 – −1103|
|English Regnal year||N/A|
|Chinese calendar||己卯年 (Earth Rabbit)
3436 or 3376
— to —
庚辰年 (Metal Dragon)
3437 or 3377
|- Vikram Samvat||796–797|
|- Shaka Samvat||662–663|
|- Kali Yuga||3841–3842|
|Igbo calendar||−260 – −259|
|Japanese calendar||Tenpyō 12
|Minguo calendar||1172 before ROC
|Thai solar calendar||1283|
|Wikimedia Commons has media related to 740.|
Year 740 (DCCXL) was a leap year starting on Friday (link will display the full calendar) of the Julian calendar. The denomination 740 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.
- October 26 – An earthquake strikes Constantinople and the surrounding countryside, causing destruction to the city's land walls and buildings, and many deaths.
- The reign of King Sevar, and thus of the House of Dulo, ends in Bulgaria.
- Pippin III marries Bertrada of Laon.
- Rebellion of the Berber tribes in the recently conquered region of Galicia. This facilitates the establishment of an independent kingdom in the Cantabrian Mountains under Alfonso I of Asturias.
- September – The Daysan River floods Edessa.
- Battle of Akroinon in Anatolia, a significant Byzantine victory over the Umayyads, halts the impetus of Arab attacks into Anatolia.
- Much to the delight of the citizens of Chang'an City, the Chinese Tang Dynasty government orders fruit trees to be planted along every main avenue of the city, which enriches not only the diets of the people but also the surroundings.
- After two unsuccessful attempts to crush the quickly spreading revolt of Tanger, the Umayyad suffer a humiliating defeat at the "battle of the Nobles" near the Chelif river.
- The Khazars, a nation of the Black Sea steppe, though not ethnically Jewish, voluntarily convert to Judaism.
- St. Cuthbert becomes archbishop of Canterbury.
- Abdallah al-Battal, Umayyad military leader
- Saint Æthelwald, Bishop of Lindisfarne
- Zhang Jiuling, poet, scholar, and ex-Chancellor of Tang China (b. 673)
- Zayd ibn Ali, Fifth Zaidi Shia Imam, (in a Shi'ite revolt in Kufa)
- Wu Daozi, Chinese painter (born 680)
- Meng Haoran, Chinese poet (born 689)
- Hilderic, duke of Spoleto
- de Oliviera Marques, A. H. (1993). "O Portugal Islâmico". In Joel Serrão and A. H. de Oliverira Marques. Hova Historia de Portugal. Portugal das Invasões Germânicas à Reconquista. Lisbon: Editorial Presença. p. 123.
- Gilbert Meynier (2010) L'Algérie cœur du Maghreb classique. De l'ouverture islamo-arabe au repli (658-1518). Paris: La Découverte; p.25.