Year 1065 (MLXV) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar.

• December 24 – King Ferdinand I of León ("the Great") dies in León, Spain, after an 11-year reign as Emperor of All Spain. His kingdom is divided among his three sons: the eldest Sancho II, the second Alfonso VI and the youngest García II. The kingdoms of Galicia and Portugal become independent under the rule of García.

• October 3 – Northumbria revolts against Tostig Godwinson, who is exiled. He takes refuge with his brother-in-law, Count Baldwin V in Flanders (modern Belgium). The Northumbrian nobles choose Morcar (or Morkere) as earl at York.
• December 28 – Westminster Abbey is consecrated by King Edward the Confessor.^[1]

• Alp Arslan, leader of the Seljuk Turks, campaigns against the Kipchaks and the Türkmen in Central Asia. He captures the city of Kars and plunders the western provinces of Georgia.

• Sima Guang, chancellor of the Song dynasty, heads a team of scholars in initiating the compilation of an enormous written universal history of China, known as the Zizhi Tongjian.

• Great German Pilgrimage of 1064–65: A large pilgrimage led by Siegfried I (archbishop of Mainz) arrives in Jerusalem after having been attacked by Bedouin bandits. Two weeks later (in April) they return to Ramla and take ships back to Latakia.
• Gregory II the Martyrophile is consecrated as catholicos of the Armenian church in Tzamandos

• A "guest star" (i.e. a nova of some kind) is observed from China. It may be related to the Strottner-Drechsler Object 20 nebula.^[2]

• Agnes of Rheinfelden, duchess of Swabia (d. 1111)
• Callixtus II, pope of the Catholic Church (d. 1124)
• Guarinus of Sitten, bishop of Sion (approximate date)
• Henry I (the Long), German nobleman (d. 1087)
• Hugh VII of Lusignan, count of La Marche (d. 1151)
• Humbert II (the Fat), count of Savoy (d. 1103)
• Li Jie, Chinese writer of the Song Dynasty (d. 1110)
• Niels (or Nicholas), king of Denmark (d. 1134)
• Richard de Montfort, French nobleman (d. 1092)
• Robert II, count of Flanders (approximate date)
• Sibylla of Burgundy, duchess of Burgundy (approximate date)
• Stephen I, count palatine of Burgundy (d. 1102)
• Vladislaus I, duke of Bohemia (approximate date)
• Walter Tirel (or William Rufus), English nobleman

• February 7 – Siegfried I, count of Sponheim
• May 17 – Egilbert (or Engelbert), bishop of Passau
• May 18 – Frederick, duke of Lower Lorraine
• June 27 – George the Hagiorite, Georgian calligrapher (b. 1009)
• July 22 – Ibn Abi Hasina, Arab poet and panegyrist (b. 998)
• July 23 – Gunther of Bamberg, German nobleman
• December 24 – Ferdinand I (the Great), king of León and Castile
• Diarmaid mac Tadgh Ua Ceallaigh, king of Uí Maine
• Ermengol III (or Armengol), count of Urgell (b. 1032)
• Gisela (or Gizella), queen consort of Hungary (b. 985)
• Gomes Echigues, Portuguese knight and governor (b. 1010)
• Gusiluo, Tibetan religious leader of Buddhism (b. 997)
• Llywelyn Aurdorchog, Welsh nobleman (approximate date)
• Thorfinn (the Mighty), Norse nobleman (approximate date)