This paper examines a critical area of interpreting research – assessment – as it pertains to the training of signed language interpreters (SLIs). The idea of testing as a wholly objective assessment of competence is problematized and issues that impact the testing cycle are teased out. These include the design and use of appropriate testing mechanisms. The attitude and expectations of external raters is analyzed, as is internal self-assessment as a means of creating active engagement in learning, and developing critical evaluation skills for later use in professional practice. We briefly consider a small number of empirical case studies that have explored aspects of assessing student interpreters. Finally, we draw attention to established pan-European frameworks, specifically the Bologna Process, for modelling fitness to practice at undergraduate and graduate level and usefulness in assessing the competencies of graduating interpreters. Given the limited empirical research that exists on the assessment of SLIs, this chapter suggests a number of themes where further studies would be beneficial.