Sir Richard Reynell, 1st Baronet (1626 – 18 October 1699), was an English-born judge who had a distinguished career in Ireland and held office as Lord Chief Justice of the King's Bench in Ireland. He was the first of the Reynell baronets of Laleham.
He was born in Devonshire, second son of Sir Richard Reynell of East Ogwell and his wife (and cousin) Mary Reynell. The Reynells were an ancient West Country family, who were descended from Sir Richard Reynell, a prominent Crown servant who lived in Somerset in the time of Richard I.
Richard entered Middle Temple in 1642 and was called to the Bar in 1653. He decided to pursue a legal career in Ireland and was admitted to the King's Inn in 1658. He built up a large practice and was noted for his willingness to take Roman Catholic clients, which was to cause him some political trouble later. He was elected to the Irish House of Commons as member for Athboy in 1661. He acted as a judge of assize, was made Second Sergeant and knighted in 1673. He enjoyed the particular friendship of Arthur Capel, 1st Earl of Essex, the Lord Lieutenant of Ireland.
On Essex's recommendation Reynell was made a judge of the Court of King's Bench (Ireland) in 1674. Essex praised him as one of the two best judges in Ireland. On the return of James Butler, 1st Duke of Ormonde to the Lord Lieutenancy in 1677, Essex before returning to England recommended Reynell to him as one of the few Irish judges who was a man of learning, and neither too old nor too ill to perform his duties effectively. Ormonde agreed: and as John Bysse, the Chief Baron of the Irish Exchequer was in failing health, the Duke proposed that Reynell should replace him. However the anti-Catholic hysteria engendered by the Popish Plot was then at its height and Reynell's tolerant attitude to Catholics told against him; nor, despite his aristocratic background, did he have much influence at Whitehall. When Bysse died Charles II chose Henry Hene to replace him. Reynell was however made a baronet (which was not a common honour for an Irish judge at the time) in 1678, and a member of the Privy Council of Ireland in 1682.