Literature on temperament, personality, and mood and anxiety disorders is reviewed. The review is organized primarily around L. A. Clark and D. Watson's (1991b) tripartite model for these disorders, but other influential approaches are also examined. Negative affectivity (or neuroticism) appears to be a vulnerability factor for the development of anxiety and depression, indicates poor prognosis, and is itself affected by the experience of disorder. Positive affectivity (or extraversion) is related more specifically to depression, may be a risk factor for its development, suggests poor prognosis, and also may be affected by the experience of disorder. Other personality dimensions (e.g., anxiety sensitivity, attributional style, sociotropy or dependency, autonomy or self-criticism, and constraint) may constitute specific vulnerability factors for particular disorders. More longitudinal and measurement-based research that jointly examines anxiety and depression is needed.