Memorials and monuments often shape the narratives of public memory surrounding key events and figures, even as they help process and represent the trauma and remembered emotions that those subjects evoke. This essay develops a schema of four types of memorial ambiguity in order to provide more precise analytic tools for understanding memorials. Ambiguous physical representation, ambiguous messages, ambiguous emotions, and ambiguous political responses interrelate as parts of the rhetorical interpretation of memorials. Examples draw from national memorials such as the Iwo Jima Memorial in Washington, DC, and the USS Arizona Memorial in Hawai’i as well as regional examples like Oklahoma’s Yellow Ribbon Memorial commemorating a 1986 postal mass shooting and The Guardian atop Oklahoma’s state capitol. This typology matters to memorial scholars and memorial designers alike: those who seek to theorize memorials ought to have a more developed sense of the rhetorical nature of ambiguity, and those who seek to construct memorials ought to consider the possibly ambiguous effects of their design. Failure to understand memorial ambiguity can lead to forgotten or ineffective memorials.