Robert Hammond (1621– 24 October 1654) was an officer in the New Model Army under Oliver Cromwell during the First English Civil War and a politician who sat in the House of Commons in 1654. He is best known for his year-long role in keeping Charles I of England in custody.
Hammond was the second son of Robert Hammond of Chertsey, Surrey, and grandson of John Hammond. He matriculated at Magdalen Hall, Oxford on 20 May 1636 aged 15, but left the university without taking a degree.
Royalist pamphleteers state that Hammond began his military career under Sir Simon Harcourt. In the summer of 1642 he was a lieutenant in the list of the army destined for Ireland; on 6 July he obtained a commission as captain of a foot company of two hundred men, to be levied for the parliament in London and the adjoining counties, and on 11 March 1643 was appointed a captain in Essex's regiment of cuirassiers.
In June 1644 Hammond, then serving under Edward Massie, distinguished himself at the capture of Tewkesbury. In the following October a quarrel between Hammond and Major Grey led to a duel in the streets of Gloucester, in which Grey lost his life. Hammond was tried by court-martial, and unanimously acquitted (28 November 1644), on the ground that he had acted in self-defence. Hammond was in 1645 appointed to the command of a regiment of foot in the New Model Army. At the battle of Naseby Hammond's regiment formed part of the reserve. He took part in the storming of Bristol and Dartmouth and in the battle of Torrington, and captured Powderham Castle and St. Michael's Mount. In October 1645, during the siege of Basing House, Hammond was taken prisoner by the garrison, and when that garrison was captured Oliver Cromwell sent him up to London, to give the House of Commons an account of the victory. The commons voted him £200 to recoup his losses as a prisoner.