Personality and psychopathology are increasingly recognized as tightly linked domains of study, despite historical and theoretical divisions. In this paper, we discuss the history of these divisions, models of inter-relations between personality and psychopathology, and selected examples from the literature demonstrating personality/psychopathology inter-relations in clinical and community populations. We begin by summarizing how personality, temperament, and personality disorders are increasingly conceptualized as overlapping entities. We next address relationships between personality traits and common mental illnesses/symptoms (e.g. internalizing and externalizing problems). Then we discuss the various ways in which personality traits may relate to Axis I conditions causally, with methods for distinguishing between them. We conclude with a more in-depth example, relating personality traits to schizophrenia.