Sitting at the heart of determining eligibility for asylum, and therefore the most crucial part of a claim that for many means the difference between life and death, the importance of demonstrating credibility cannot be overstated. Yet credibility does not lend itself to straightforward quantification or measurement, and those measures on which we do rely are imperfect and highly subjective. This dissertation asks how the evolution of cultural ideas about credibility shape the form of asylum claims, and in light of this process, how asylum-seekers navigate competing demands to make credible claims of persecution and fear. I argue that by analyzing asylum narratives we can observe the nature and function of credibility both in the specific institutional context of adjudicating claims, and in the broader political and cultural contexts of defining and measuring truth. To understand how asylum seekers legally and discursively construct credibility I ask: (1) How do asylum seekers construct credibility in their written and oral narratives? (2) How are claims shaped by the institutional environment in which decisions are made and the evolution of cultural ideas about credibility? (3) How are the construction and contestation of credibility informed by the nature of the claimant’s identity and experience? and, lastly (4) How and why does the construction and contestation of credibility change over time?