Assessment of prior learning (APL) refers to the process of acknowledging adults’ formal, informal and non-formal learning, representing a relatively new and expanding practice around the world. In higher education, APL is used to gain access and credits due to skills and knowledge acquired inside and, more importantly, outside formal academic settings. Considering the impact that the result of APL has on future working career, this assessment can be regarded as a high stake for the claimants of APL. In high-stake assessments it is vital that central quality criteria are met, and they also require an extensive evaluation of the fully developed assessment in use (AERA, APA, & NCME, 2004; Moss, Girard, & Haniford, 2006). However, a review examining research on APL reveals that the problem of reliability in the assessment is very rarely examined (Stenlund, 2010). That means that the trustworthiness of the practices underpinning the process of APL is not questioned. The purpose of this article is to provide a better understanding of issues related to the reliability of APL.