David Rizzio (approx. 1533-9 March 1566) was the private secretary of Mary I of Scotland, and Mary's husband, Darnley, was jealous of their friendship and so joined in a conspiracy of Protestant nobles to murder him.

Rizzio or (Riccio) had arrived at the Scottish court in 1561, one of the staff of the ambassador from Savoy. He was handsome (see the detail of his portrait, possibly an unfinished miniature), and a good musician. Towards the end of 1564, he became the Queen's secretary for relations with France. Ambitious, seeing himself as all but a secretary of state, a Catholic, and a foreigner to boot, Rizzio had the Queen's ear, and perhaps more of her person, it was rumored. Jealousy precipitated his murder in the Queen's presence, in her supper chamber at Holyroodhouse. He was stabbed, allegedly 57 times.

Rizzio's murder was only an incident in the larger campaign by Scottish nobles to contain and control the Queen.