The 1150s was a decade of the Julian Calendar which began on January 1, 1150, and ended on December 31, 1159.
- Cubbie Roo's Castle is built on Wyre, Orkney.
- A Benedictine priory is founded at Birkenhead, England, resulting in the first recorded Mersey Ferry.
- Christchurch Priory is founded in Dorset, England.
- Castle Rising is built in Norfolk, England by William d'Aubigny, 1st Earl of Arundel.
- The University of Paris, now known as the Sorbonne, is founded.
- Christian Malone writes his Irish Chronology (Chronicum Scotorum).
- The city of Neuruppin is founded in Brandenburg, Germany.
- The city of Rinteln is founded in Lower Saxony, Germany.
- Middle Dutch begins to be spoken in the Low Countries.
- Peter the Lombard publishes Sentences.
- Dryburgh Abbey is founded by Hugh de Morville, Constable of Scotland).
- The first doctorate degree is awarded in Paris, France.
- Battle of Tara: The Byzantine Empire defeats the Serbian Grand Principality and the Kingdom of Hungary.
- With the support of Muslim troops, the Normans suppress a rebellion on the Sicilian-controlled island of Djerba, and invade the island of Kerkenna.
- January 6 – Henry of Anjou arrives in England, hoping to dethrone the reigning monarch, Stephen of England, and replace him with Henry's mother, Empress Matilda.
- May 24 – Malcolm IV succeeds his grandfather as King of Scotland at the age of 12, and on May 27 is crowned at Scone Priory.
- November 6 – The Treaty of Wallingford, under the direction of Theobald of Bec, reconciles Stephen of England and Matilda, ending "The Anarchy" which has occurred during their fight for the throne of England. The treaty grants the throne to Stephen for the duration of his life, but makes Matilda's son, Henry of Anjou, the heir apparent.
- The city of Oberglatt (in modern-day Switzerland) is first mentioned in written literature.
- Confronted with important financial difficulty due to the expenses of its Spanish crusade, the Republic of Genoa has to sell its third of the city of Tortosa (which had been conquered in 1148 during that same crusade) to the Count of Barcelona.
- February 26 – Roger II of Sicily dies at Palermo. He is succeeded by his youngest son, William I of Sicily.
- October 25 – Stephen, King of England dies at Dover, and is succeeded by Henry Plantagenet, the son of his cousin Matilda.
- December 14 – Pope Adrian IV (also known as Hadrian IV) succeeds Pope Anastasius IV, as the 169th pope. Born Nicholas Breakspear, he is the only English pope in history.
- December 19 – King Henry II of England, aged 21, is crowned along with his wife Eleanor of Aquitaine.
- The Château de Chinon is built by Theobald I, Count of Blois.
- The Almohad army conquers the last independent Muslim stronghold in Spain, Granada, after six years of siege.
- Birmingham, England, and the Birmingham Bull Ring are founded.
- Bosnia becomes an autonomous duchy.
- Belgrade is rebuilt by Byzantine emperor Manuel I Komnenos.
- Tallinn, the capital of Estonia, is first marked on the world map by Muhammad al-Idrisi.
Arts and culture
January 15 – Muhammad al-Idrisi completes his atlas of the world, the Tabula Rogeriana, which will remain one of the most accurate maps until the Age of Discovery.
- Sfax revolts against the Norman occupiers, and massacres the Christians found in the city.
- January 20 – According to legend, freeholder Lalli slays English crusader Bishop Henry with an axe, on the ice of Lake Köyliönjärvi in Finland.
- December 25 – King Sverker the Elder is murdered on his way to church, and is soon succeeded as king of Sweden by his rival, Eric Jedvardsson.
- Prince Yuri Dolgorukiy founds and fortifies Moscow.
- The Privilegium Minus elevates Austria to the status of a duchy, ruled by the Babenburgs family.
- Mosan artists create the Stavelot Triptych, a masterpiece of goldsmithing, as a reliquary to house purported pieces of the True Cross.
- A rebellion breaks out against William I of Sicily, and the Byzantine Empire, encouraged by Pope Adrian IV, invades Apulia. William II crushes the rebellion, defeats the Byzantine armies at Brindisi, and humbles the Pope at Benevento. The city of Bari is laid to waste for the coming ten years.
- Raynald of Châtillon sacks Cyprus.
беларуская (тарашкевіца): 1150-я
srpskohrvatski / српскохрватски: 1150-e