Agnes Prest (died 15 August 1557) was a Cornish Protestant martyr from the reign of the Catholic Queen Mary. She was burned at the stake at Southernhay in Exeter in 1557. According to Foxe's Book of Martyrs, and the story of Exeter Protestant Martyrs she lived near Launceston, Cornwall, and was married to a Catholic husband. She left her husband over his Catholicism, and went to be a spinner but she later on returned to him and was arrested and indicted at the Launceston Assizes. She was then put in Launceston jail and then transferred to Exeter jail. In Exeter jail, she was brought before the Bishop of Exeter, Bishop Turberville. When questioned, she denied the Catholic doctrine of transubstantiation. She was then released for a month.