This article draws on recent scholarship on Shakespearean allusions and crime fiction to develop an in-depth exploration of Agatha Christie's quotations from the playwright. These quotations do not tend to point to the murderer or give clues to the plot, but fall into three major categories. In some novels she uses them to interpolate the reader within the layers of intertextuality within crime fiction, aligning them with the author and with the detective rather than other characters. In other novels she uses discussions of Shakespeare to position her characters in the midcentury " feminine middlebrow " mode of novels identified by Nicola Humble. In a trio of late novels, her characters use reflections on how Macbeth should be staged to gain insights about the dangerous worlds they inhabit. The article examines how the novels engage with the Shakespearean text, but also with the shifting conceptions of Shakespeare which developed during the twentieth century. It reveals a sophisticated set of textual strategies within Christie's novels, which debate the meaning of Shakespeare's plays, and stage controversies over the ways in which those meanings should be accessed and reproduced.