The construct of personality dysfunction has received considerable attention in the last two decades as both clinicians and researchers have sought to further our understanding of what constitutes personality pathology beyond maladaptive-range traits. A clear goal of this work has been to determine whether personality dysfunction is an essential component of personality disorder. To achieve this goal, crucial questions must be answered, including (a) what is the structure of personality dysfunction, (b) how can we best explain the overlap between personality dysfunction and traits theoretically, and (c) how can we best ensure that empirical measures of each of these components reflect their theoretically hypothesized overlap. Efficient personality dysfunction measures that are both theoretically based and psychometrically robust are needed to help answer such questions. For my first-year project, I developed a short form of the Generalized Assessment of Personality Dysfunction (GAPD; Livesley, 2010), a prominent and influential measure of personality dysfunction. In this Master's thesis, I examine the psychometric properties and construct validity of this short form, named the GAPD – Three Brief Factor Form (GAPD-3BFF). The GAPD-3BFF demonstrated (a) improved reflection of theory, (b) strong psychometric properties, (c) partial ability to differentiate among samples with varying levels of psychopathology, (d) good convergent validity but variable discriminant validity, and (e) moderate ability to predict personality pathology, although it had little incremental predictive power over measures of maladaptive-range traits. Thus, the GAPD-3BFF is a psychometrically robust and efficient measure with a clear theoretical basis that can play an important role in the field's effort to further our understanding of personality dysfunction. However, it also shares limitations of existing measures of the construct (e.g., insufficient discriminant validity both among some aspects of personality dysfunction and with personality traits), indicating the need for a new measure that addresses such limitations.