|Centuries:||11th century – 12th century – 13th century|
|Decades:||1090s 1100s 1110s – 1120s – 1130s 1140s 1150s|
|Years:||1123 1124 1125 – 1126 – 1127 1128 1129|
- January–March – In Song Dynasty China, scholars and farmers demonstrate around Kaifeng for the restoration of a probity military official, Li Gang (李綱). Small conflicts erupt between the protestors and the Government.
- Two previously written Chinese pharmaceutical works, one by Shen Kuo and another by Su Shi, are combined into one written work.
- The rule of Emperor Huizong of Song ends in China.
- The Jin Dynasty is established in the north of China, following the Song Dynasty's loss at the Huang He River valley. Remnants of the court flee south, including much of the populace and communities such as the Kaifeng Jews.
- Rutherglen becomes one of the first Royal Burghs in Scotland.
- Ragnvald Knaphövde, pretender to the Swedish throne, is killed by upset peasants at a local thing. Sweden is without ruler, but Magnus the Strong claims sovereignty over Gothenland for the time being.
- Alfonso VII is crowned king of Castile and León in Spain.
- King Alfonso the Battler of Navarre and Aragon launches a raid into Granada.
- The Venetians occupy Cephalonia. Byzantine Emperor John II Komnenos restores their trading privileges.
- Olegarius creates the community of knights known as the confraternity of Tarragona to combat the Andalusians in Catalonia.
- Adelard of Bath translates Muḥammad ibn Mūsā al-Ḵwārizmī's arithmetic and astronomical tables into Latin.
- February 10 – William IX, Duke of Aquitaine and poet (b. 1071)
- March 8 – Queen Urraca of Castile (b. 1082)
- October 1 – Morphia of Melitene, Queen of Jerusalem
- Edgar Ætheling, last member of the Anglo-Saxon royal house (b. 1052)
- Ragnvald Knaphövde, pretender to the Swedish throne (killed by upset peasants at the thing)
- Abbot Ekkehard of Aura
- Omar Khayyam, Persian poet and mathematician