The studies of emotion function and emotional disorders complement one another. In this article, the authors outline relations between the social functions of emotion and four psychological disorders. The authors first present a social-functional account of emotion and argue that emotions help coordinate social interactions through their informative, evocative, and incentive functions. They then review evidence concerning the emotional and social problems related to depression, schizophrenia, social anxiety, and borderline personality disorder and consider how the emotional disturbances related to these disorders disrupt interactions and relationships, thus contributing further to the maintenance of the disorder. They conclude by discussing research strategies relevant to the study of emotion, social interaction, and psychopathology.