Æthelstan was an 11th-century Catholic bishop who served the diocese of Hereford. Consecrated sometime between 1013 and 1016, he led his see during a period of significant regional instability. In the final thirteen years of his life, he suffered from blindness, which necessitated the appointment of Tremerig as a suffragan bishop to assist him. His tenure coincided with ongoing tensions along the Welsh border, requiring the bishops of Worcester to take on defensive responsibilities for the region.