Matilda was born in February, possibly the 7th or 11th, 1102 to Henry I of England and his wife Edith-Matilda of Scotland. Her maternal grandparents were Malcolm III of Scotland and Saint Margaret of Scotland. Margaret was a daughter of Edward the Exile and granddaughter of Edmund II of England.

Her birth is generally said to have taken place at Winchester, though recent research by the late John Fletcher, who died in 1990, suggests it may have occurred at the royal palace at Sutton Courtenay in Berkshire, now Oxfordshire

When she was seven years old, Matilda was betrothed to Henry V, Holy Roman Emperor, and was sent to the Holy Roman Empire in 1111 to begin her training as his consort. Matilda and Henry were married at Worms on 7th January 1114 in a splendid ceremony. In March 1116 Matilda and Henry visited Rome and Tuscany, and she acted as Regent in his absence.

The Imperial couple allegedly had no surviving offspring; Hermann of Tournai states that Maud bore a child that lived only a short while. When Henry died in 1125, he left Matilda a "childless" widow of twenty-three. Her brother William Adelin had perished several years before in the wreck of the White Ship, leaving Matilda the only legitimate heir to the English throne.

Despite being known most popularly by the title of 'Empress' in after years due to her first marriage, Matilda's right to the title was dubious. She was never crowned Holy Roman Empress by a legitimate Pope, which was generally recognised as required to claim the title, only as Queen Consort of Germany by her husband's Bishops and formally her correct title was 'Queen of the Romans'. However, "Empress" was arguably an appropriate courtesy title for the wife of the Emperor, who had been crowned by the Pope, and indeed, in later years she encouraged chroniclers to believe that the Pope had crowned her.

Matilda returned to the Kingdom of England, where her father named her his heir with the agreement of the Anglo-Norman barons, who swore in 1127 to accept her as ruler if Henry I had no son, and arranged another marriage for her. On 17th June 1128, she was married again, at Le Mans in Anjou, to Geoffrey of Anjou, who was eleven years her junior. He was nicknamed "Plantagenet" from the broom flower (planta genista) which he took as his emblem, hence the name of the line of English kings descended from him. He was at this time Count of Maine and heir to his father Fulk V of Anjou.

The marriage was not a happy one, and Matilda separated from him and returned to her father. She returned to Geoffrey in 1131, and they were reconciled. They produced three sons, the eldest of whom, Henry, was born on 5th March 1133. The birth of her second son, Geoffrey, Count of Nantes, in 1134 was difficult and Matilda nearly died in childbirth. Her third son was William, Count of Poitou. Her father King Henry came to visit and took "great delight" in his grandsons. King Henry and Geoffrey quarrelled, and so when her father died on 1st December 1135 in Normandy, Matilda was with Geoffrey in Anjou.

On the death of her father, Henry I, in 1135, Matilda expected to succeed to the throne of England, but her cousin, Stephen of Blois, the grandson of William I,  usurped the throne, breaking the oath he had previously made to defend her rights, with the support of most of the barons. An immediate reason for this was that Stephen was in England, whilst Matilda was in Anjou. The civil war which followed was bitter and prolonged, with neither side gaining the ascendancy for long, but it was not until 1139 that Matilda could command the military strength necessary to challenge Stephen within his own realm, including battles at Beverston Castle and other sites. Stephen's wife was another Matilda: Matilda, Countess of Boulogne, and the Empress's maternal cousin. During the war, Matilda's most loyal and capable supporter was her half-brother, Robert of Gloucester.

Matilda's greatest triumph came in April 1141, when her forces defeated and captured King Stephen at the Battle of Lincoln. He was made a prisoner and effectively deposed. Although she now controlled the kingdom, Matilda never styled herself Queen but took the title "Lady of the English", possibly modelled on the Anglo-Saxon practice of naming female rulers "Lady of the..." such as King Alfred the Great's daughter Ethelfleda, Lady of the Mercians. Her advantage lasted only a few months. When she marched on London, the city was ready to welcome her and support a coronation. However, she refused the citizens' request to have their taxes halved. On 24th June 1141, she found the gates of London shut and the civil war reignited. By November, Stephen was free, having been exchanged for the captured Robert of Gloucester, Matilda's half-brother, and a year later, the tables were turned when Matilda was besieged at Oxford but escaped to Wallingford, supposedly by fleeing across the snow-covered land in a white cape. In 1141 she had escaped Devizes in a similarly clever manner, by disguising herself as a corpse and being carried out for burial. In 1148, Matilda was finally forced to return to France, following the death of Robert of Gloucester.

All hope was not lost. Matilda's son, Henry, later, Henry II of England, was showing signs of becoming a successful leader. Although the civil war had been decided in Stephen's favour, his reign was troubled. In 1153, the death of his son Eustace, combined with the arrival of a military expedition led by Henry, led him to acknowledge the latter as his heir by the Treaty of Wallingford.

Matilda retired to Rouen, in Normandy, during her last years, where she maintained her own court and presided over the government of the Duchy in the absence of Henry. She intervened in the quarrels between her eldest son Henry and her second son Geoffrey, but peace between the brothers was brief. Geoffrey rebelled against Henry twice before his sudden death in 1158. Relations between Henry and his youngest brother, William, were more cordial, and William was given vast estates in England. Archbishop Thomas Becket refused to allow William to marry the Countess of Surrey and the young man fled to Matilda's court at Rouen. William, who was his mother's favourite child, died there in January 1164, reportedly of disappointment and sorrow. She attempted to mediate in the quarrel between her son Henry and Thomas Becket, but was unsuccessful.

Despite her tenure as "Lady of the English", Matilda was never loved by the people of her native land, who found her too foreign and haughty. The citizens of London were particularly aggrieved by her financial demands. She spoke three languages: French, German, and Latin. Even though she gave up hope of being crowned Queen in 1141, her name always preceded that of her son Henry, even after he became king. Matilda died at Rouen, and was buried in the cathedral there; her epitaph reads: "Great by Birth, Greater by Marriage, Greatest in her Offspring: Here lies Matilda, the daughter, wife, and mother of Henry."