Sir Richard Osbaldeston (c.1585 – 1640) was an English barrister who became Attorney General for Ireland. He was the great-grandfather of Richard Osbaldeston, Bishop of London.
He was born in Lancashire, probably at Sefton. His father Edward Osbaldeston (died 1639), belonged to an ancient Lancashire family, the Osbaldestons of Osbaldeston. Edward's father was the youngest son of a large family, but Edward himself made an advantageous marriage to Margaret Molyneux, a member of the family which later took the title Earl of Sefton. They were also related to the Earl of Derby, and profited from this connection. By the 1620s they were rich enough to buy the Manor of Hunmanby in Yorkshire, where they remained until the family died out in the 1830s.
Richard entered Gray's Inn and was called to the Bar. Few details of his career as a barrister survive but it is likely that he practiced mainly in York, where he was living at the time of his first marriage in 1612.
In 1636 he was knighted and sent to Ireland as Attorney General: he had a link with the Irish bench through his cousin Geoffrey Osbaldeston, Chief Justice of Connacht (died c.1635) who had a long if undistinguished record of service to the Crown. Richard is said to have been a close associate of the Lord Deputy of Ireland, Thomas Wentworth, 1st Earl of Strafford, a fellow Yorkshireman, who may have known him in earlier days. Wentworth frequently consulted him on legal points, but given the Lord Deputy's overwhelming personality and his absolute control of the Irish government, it is unlikely that any legal adviser had much influence over him.