Current methods for the assessment of personality disorders do not systematically capture withinperson variability across time or contexts, but rather consider personality disorders as static constructs. Recent research, however, has shown that within-person variability is substantial and clinically relevant for the understanding of personality disorders. The current research proposal addresses the need for alternative assessment strategies that do incorporate this within-person variability on personality disorder traits, thereby acknowledging that people’s behavior and experiences are always embedded in a specific context. The relative contribution of within-person variability beyond what is explained by traditional assessment procedures (clinical interviews and personality inventories) will be empirically examined, and its congruence with experience sampling data will be explored. Towards this end, a specific situational judgment test for personality disorders will be constructed, relying on a well-established empirically-based situational taxonomy, that enables to generate relevant scenarios along psychologically meaningful dimensions of situations. With this proposal, we aim to contribute to the complex field of personality pathology assessment and strongly believe in the potential and surplus value of situational judgement tests in this area, because they directly assess the dynamic nature of psychopathology.