Robert Cooke (or Cook) (born c. 1535, died 1592–3) was an English Officer of Arms in the reign of Elizabeth I. In the College of Arms, he rose to the rank of Clarenceux King of Arms, serving in that capacity from 1567 until his death in 1592–3. He served as marshal for the state funeral of Sir Philip Sidney in 1587. Cooke was accused by fellow officers of arms of granting arms to unworthy men for personal gain.
Cooke is supposed to have been the son of a tanner and to have been brought up in the household of Sir Edmund Brudenell, an ardent genealogist. Cooke matriculated as a pensioner in St. John's College, Cambridge, 10 November 1553, earning his BA there in 1557–8. He was appointed Rose Blanche pursuivant extraordinary, 25 January 1561–2 and succeeded William Flower as Chester Herald of Arms four days later. Both events were recorded in the diary of Henry Machyn, who twice identified Cooke as the servant of Lord Robert Dudley. Cooke was promoted to Clarenceux King of Arms on 21 May 1567. Cooke was appointed Acting Garter King of Arms on the death of Sir Gilbert Dethick on 3 October 1584, and served in that capacity until the permanent appointment of Sir Gilbert's son William Dethick on 21 April 1586. As acting Garter, Cooke, assisted by Robert Glover, Somerset Herald, accompanied the Earl of Derby to France to invest King Henri III with the Order of the Garter in 1584.