The developmental pathways leading to personality disorders are poorly understood, but clues to these pathways come from recent research on personality disorders and normal personality development in childhood and adolescence. The first section of this paper reviews recent work on personality disorders in childhood and adolescence, and concludes that personality disorders in adolescence are already prevalent, moderately stable, and impairing. The second section draws on McAdams and Pals' personality model to offer a taxonomy of personality differences that can account for the known patterns of emerging personality pathology. This taxonomy includes youths' temperament and personality traits, mental representations (including attachment), coping strategies, and narrative identities. Individual differences in all of these domains may play critical roles in the development, manifestation, and course of personality disorders. Existing knowledge of normal and abnormal personality development can inform future research on the developmental pathways leading to personality pathology, the diagnostic criteria for personality disorders, and the development of validated treatments for personality disorders in the first two decades of life.