Surfeit of Lampreys is a detective novel by Ngaio Marsh; it is the tenth novel to feature Roderick Alleyn, and was first published in 1941. The plot concerns the murder of a British peer, a theme to which Marsh would return; the novel was published as Death of a Peer in the United States. Its title is a reference to the manner by which Henry I of England is said to have succumbed to food poisoning, as well as the surname of the first murder victim, and his family, who fall under suspicion.