The 12th century is the period from 1101 to 1200 in accordance with the Julian calendar. In the history of European culture, this period is considered part of the High Middle Ages and overlaps with what is often called the "'Golden Age' of the Cistercians". The Golden Age of Islam experienced significant development, particularly in Islamic Spain.

In Song dynasty China an invasion by Jurchens caused a political schism of north and south. The Khmer Empire of Cambodia flourished during this century, while the Fatimids of Egypt were overtaken by the Ayyubid dynasty. Following the expansions of the Ghaznavids and Ghurid Empire, the Muslim conquests in the Indian subcontinent took place at the end of the century.

Events

1101–1109

• 1101: In July, the Treaty of Alton is signed between Henry I of England and his older brother Robert, Duke of Normandy in which Robert agrees to recognize Henry as king of England in exchange for a yearly stipend and other concessions. The agreement temporarily ends a crisis in the succession of the Anglo-Norman kings.
• 1101–1103: David the Builder takes over Kakheti and Hereti, (now parts of Georgia).
• 1102: King Coloman unites Hungary and Croatia under the Hungarian Crown.
• 1102: Muslims conquer Señorio de Valencia
• 1103–1104: A church council is convened by King David the Builder in Urbnisi to reorganize the Georgian Orthodox Church.
• 1104: In the Battle of Ertsukhi, King David the Builder defeats an army of Seljuks.
• 1104: King Jayawarsa of Kadiri (on Java) ascends to the throne.
• 1106: Battle of Tinchebray
• 1107–1111: Sigurd I of Norway becomes the first Norwegian king to embark on a crusade to the Holy Land. He fights in Lisbon and on various Mediterranean isles and helps the King of Jerusalem to take Sidon from the Muslims.
• 1108: By the Treaty of Devol, signed in September, Bohemond I of Antioch has to submit to the Byzantine Empire, becoming the vassal of Alexius I.
• 1109: On June 10, Bertrand of Toulouse captures the County of Tripoli (northern Lebanon/western Syria).
• 1109: In the Battle of Nakło, Boleslaus III Wrymouth defeats the Pomeranians and re-establishes Polish access to the sea.
• 1109: On August 24, in the Battle of Hundsfeld, Boleslaus III Wrymouth defeats Emperor Henry V of Germany and stops German expansion eastward.

1110s

• 1111: On April 14, during Henry V's first expedition to Rome, he is crowned Holy Roman Emperor.
• 1113: Paramavishnulok is crowned as King Suryavarman II in Cambodia.