Murder Must Advertise is a Lord Peter Wimsey mystery novel by Dorothy L. Sayers, published in 1933. Most of the action takes place in an advertising agency, a setting with which Sayers was very familiar. It is often considered to be the best book of the Wimsey series, although she herself considered it something of a failure.
Murder Must Advertise was adapted for television in 1973 as part of a series starring Ian Carmichael as Lord Peter.