Ryves, Sir William (d. 1648), judge, was the sixth son of John Ryves of Blandford, Dorset, and his wife, Elizabeth, daughter of Sir John Mervyn of Fonthill, Dorset. He entered the Middle Temple in 1593 and was called to the bar seven years later. In 1619 he appears as a bencher at the Middle Temple and was appointed second justice of the Carmarthern circuit. The same year, Sir John Davies (qv), whose wife was a sister of Ryves's aunt, arranged for Ryves to succeed him as attorney general of Ireland. Davies presumably also arranged Ryves's knighthood from James I on 10 November 1619. Ryves went to Ireland shortly after 30 October 1619 when he was appointed attorney general.
Unlike his predecessor in this post, Ryves did not attempt to influence government policy and appears to have acted mainly as a cog in the administrative machine. On 7 August 1636 he resigned as attorney general to become third justice of the court of king's bench. From 1620 to 1641 he appears frequently as justice of the assize, generally on the Leinster circuit. During his service in Ireland he acquired lands at Rathsallagh, Co. Wicklow, at Corron, Co. Carlow, and probably elsewhere. He sat as MP for Belturbet, Co. Cavan, in 1634–5, became treasurer of the King's Inns in 1639 and acted as speaker of the Irish house of lords in 1641–2.
He lost all his land in Ireland following the October 1641 catholic rebellion. He was back in England in September 1642, intending to return to the bar. However, the outbreak of the English civil war soon afterwards frustrated his plans. Ryves was a strong royalist and on 20 September 1642 he was appointed one of the king's learned counsel extraordinary. He was still in England in September 1643, but he had returned to Dublin by March 1645, and provided the Dublin administration with legal advice during the negotiations with the Catholic Confederation in 1644–5. He was in England again in 1647, but died in Dublin in 1648; he was buried in St John's church. He married twice: first a woman named Jackman, and second Dorothy, daughter of John Waldron.