Robert Sibthorpe or Sibthorp (died 1662) was an English clergyman who gained notoriety during the reign of King Charles I of England for his outspoken defense of the divine right of kings.
Sibthorpe was a fellow of Trinity College, Cambridge, receiving his M. A. from that institution in 1619. He became vicar of The Holy Sepulchre, Northampton in 1619. He received his D.D. ca. 1626.
Sibthorpe first gained national prominence in 1627, when he gave an assize sermon in which he asserted the doctrine of passive obedience. King Charles I wanted to have Sibthorpe's sermon, along with a similar sermon delivered by Roger Maynwaring, printed. George Abbot, Archbishop of Canterbury opposed the publication of these sermons, but William Laud, Bishop of Bath and Wells urged George Montaigne, Bishop of London to license the publication and as a result the sermons were published. (Laud was promoted to Bishop of London in 1628 as a result.)
At the 1628 Parliament, John Pym moved in the House of Commons of England to impeach Sibthorpe and Maynwaring. In the House of Lords, the two were accused of subverting the commonwealth. As a result, Sibthorpe and Maywaring were imprisoned and fined; suspended from the ministry, prevented from clerical or secular advancement, and told they could not preach at Court.