Aethelberht (died 865/866) was the king of the West Saxons, or Wessex, who succeeded to the subkingdom of Kent during the lifetime of his father Aethelwulf and retained it until the death of his elder brother Aethelbald, when he became sole king of Wessex and Kent, the younger brothers Aethelred and Alfred renouncing their claim. He ruled these kingdoms for five years. His reign was marked by two serious attacks from the Danes, who destroyed Winchester, in spite of the resistance of the ealdormen Osric and Aethelwulf. The Danes also ravaged Kent.