This essay attempts to define unreliability in autobiography and explore its major forms and features in relation to unreliability in fiction. It starts with the construction of a narratological framework for autobiography, especially in terms of the narrative communicative situation. Then it goes on to discuss two contrasting approaches to fictional unreliability, the rhetorical and the cognitivist or construc-tivist. The rhetorical approach deals, in an idealized way, with the gap between the narrator and the implied author and is only concerned with the “implied ” or “autho-rial ” reader (critics who try to enter that position). The constructivist approach, by contrast, is also concerned with how actual readers try to resolve textual problems with different integration mechanisms. The present study defines and explores auto-biographical unreliability in relation to both the rhetorical model and the construc-tivist model in fiction studies. To illustrate autobiographical unreliability, this essay analyzes two autobiographies by Frederick Douglass in terms of intertextual unreli-ability and a recent Chinese autobiography in terms of extratextual (un)reliability. In both cases, the divergent responses highlight the functioning of different integration mechanisms. The analysis brings to light certain integration mechanisms peculiar to the interpretation of autobiography and, moreover, shows how the same integration mechanism can be used to opposed effects. We are very grateful to Meir Sternberg and the anonymous readers of Poetics Today for help-ful comments on earlier drafts of this essay. Poetics Today 28:1 (Spring 2007) doi 10.1215/03335372-2006-01