The Battle of Englefield was a battle on 31 December 870 at Englefield, near Reading in what is now the English county of Berkshire. It was one of a series of battles, with honours to both sides, that took place following an invasion of the then kingdom of Wessex by an army of Danes, during which the Danes had established a camp at Reading. Both battle and campaign are described in the Anglo-Saxon Chronicle.
Three days after their arrival in Reading, a party of Danes, led by two of their earls, rode out towards Englefield. Here Æthelwulf, the Ealdorman of the shire, had mustered a force and was waiting for them. In the ensuing Battle of Englefield many of the Danes – including one of the earls named Sidrac – were killed, and the rest driven back to Reading.
The Saxon victory at Englefield did not last long. Four days later, the main West Saxon army, led by King Ethelred and his brother, Alfred the Great attacked the main Danish encampment at Reading and were bloodily repulsed, in what became known as the first Battle of Reading. Among the many dead of both sides was Æthelwulf. Further battles followed, including the Battle of Ashdown, when Alfred led the Saxon forces to victory, and the Battle of Basing, when the Danes prevailed. In April 871, Ethelred died, to be succeeded by Alfred. Much of King Alfred's 28-year reign was taken up with the Danish conflict.