1118 was a common year.
|Centuries:||11th century – 12th century – 13th century|
|Decades:||1080s 1090s 1100s – 1110s – 1120s 1130s 1140s|
|Years:||1115 1116 1117 – 1118 – 1119 1120 1121|
- January 24 – Pope Gelasius II succeeds Pope Paschal II as the 161st pope.
- March 10 – Gregory VIII is elected antipope.
- June 11 – Roger of Salerno, Prince of Antioch, captures Azaz from the Seljuk Turks.
- December 18 – Alfonso the Battler expels the Moors from Zaragoza.
- Þorlákur Runólfsson becomes Bishop of Skálholt.
- Enna mac Donnchada mac Murchada becomes King of Dublin.
- Cu Faifne mac Congalaig becomes King of Ui Failghe.
- Maelsechlainn Ua Faelain becomes King of the Déisi Muman.
- The cantrefs of Rhos and Rhufoniog are annexed by Gruffydd ap Cynan, King of Gwynedd.
- The Archbishop of York is no longer required to be crowned by the Archbishop of Canterbury.
- Reconstruction begins on Peterborough Cathedral, destroyed by fire in 1116.
- Ramon Berenguer III, Count of Barcelona captures Tarragona from the Moors.
- A rebellion against Henry I of England breaks out in Normandy.
- Alberich of Rheims becomes Master at the school of Rheims.
- Charles I, Count of Flanders marries Margaret of Clermont.
- Amaury IV of Montfort divorces his wife Richilde, daughter of Baldwin II, Count of Hainaut.
- Wulgrin III becomes Count of Angoulême.
- Gervais becomes Count of Rethel.
- The castle of Montlhéry is dismantled by Louis VI of France.
- The cathedral of Ferentino is completed.
- Restoration of Santa Maria in Cosmedin begins.
- Magdeburg is almost destroyed by fire.
- Reichenbach Abbey is founded.
- Zwickau, Eisenstadt, Kirchgandern, and Wolfenbüttel are first mentioned.
- Otto of Bamberg is suspended by the Pope, and Norbert of Xanten defends himself against charges of heresy at the Synod of Fritzlar.
- Đorđe, Vojislavljevic´ ruler of Serbia, is overthrown by Uroš I of Raška.
- George of Duklja is overthrown by his cousin Grubeša.
- Radostl becomes Bishop of Krakow.
- Zbraslav, now part of Prague, is founded.
- Sylvestr becomes bishop of Pereyaslavl Yuzhniy.
- The Knights Templar are founded, with Hughes de Payens serving as the first Grand Master.
- John II Comnenus succeeds Alexius I as Byzantine emperor.
- The Byzantine general Philocales captures Sardis from the Seljuk Sultanate of Rûm.
- Baldwin I of Jerusalem invades Egypt.
- Baldwin of Le Bourg succeeds his cousin Baldwin I as king of Jerusalem.
- Roman of Le Puy becomes lord of Oultrejordain.
- Joscelin I succeeds Baldwin of Le Bourg as Count of Edessa.
- Garmond of Picquigny becomes Latin Patriarch of Jerusalem.
- Suleyman I ibn al-Ghazi becomes emir of Aleppo.
- David IV of Georgia captures Lorri from the Seljuk Turks.
- David IV of Georgia settles a number of Kipchaks in Georgia.
- Ahmed Sanjar and Mahmud II proclaim themselves rival Seljuk sultans upon the death of Mehmed I of Great Seljuk.
- Al-Mustarshid becomes Abbasid caliph.
- Bahram Shah becomes Ghaznavid emperor.
- The Hoysala Empire defeats the Chalukya at the Battle of Kennagal.
- The Zenghe era of Emperor Huizong of Song China ends, and the Chonghe era begins.
- The Yongning era of Emperor Chongzong of Western Xia ends.
- Start of the Genei era in Japan.
- November 28 – Manuel I Comnenus, Byzantine Emperor (d. 1180)
- December 21 – Thomas Becket, Archbishop of Canterbury (d. 1170)
- Gualdim Pais, Portuguese Grand-Master of the Templars (d. 1195)
- Eudes II, Duke of Burgundy
- Gertrude, daughter of Lothair III, Holy Roman Emperor and wife of Henry X, Duke of Bavaria
- Christina, daughter of Canute Lavard, wife of Magnus IV of Norway
- Andronicus I Comnenus, Byzantine Emperor (d. 1185)
- Nur ad-Din, ruler of Syria (d. 1174)
- Ahmed ar-Rifa'i, founder of the Rifa'i Sufi order
- Taira no Kiyomori, Japanese general (d. 1181)
- Saigyo, Japanese poet
- January 21 – Pope Paschal II
- April 2 – King Baldwin I of Jerusalem
- April 16 – Adelaide del Vasto, regent of Sicily, mother of Roger II of Sicily, queen of Baldwin I of Jerusalem
- May 1 – Edith of Scotland, queen of Henry I of England
- June 5 – Robert de Beaumont, 1st Earl of Leicester
- July 7 – Florence of Worcester, long thought to be the writer of the chronicle of John of Worcester
- August 15 – Alexius I Comnenus, Byzantine Emperor (b. 1048)
- Gissur Ísleifsson, Bishop of Skálholt
- Muircheartach Ua Briain, High King of Ireland
- Domnall mac Muirchertaig ua Briain, King of Dublin
- Rogan mac Domnaill meic Conchobair, King of Ui Failghe
- William, Count of Évreux
- William III, Count of Angoulême
- Lithuise of Blois
- Milo II, lord of Montlhéry
- Hugh I, Count of Rethel
- Gerberge I, Countess of Provence
- Philip Halsten, King of Sweden
- Maur, Bishop of Krakow
- Basil the Physician, Bogomil leader
- Arnulf of Chocques, Latin Patriarch of Jerusalem
- Mehmed I of Great Seljuk, Seljuk sultan
- Al-Mustazhir, Abbasid caliph
- Arslan Shah, Ghaznavid emperor