The impact of personality traits on people's attitudes and behaviors is widely recognized, yet systematic attention to personality in large-N research on elected officials has been rare. Among psychologists, five-factor frameworks that focus on openness to experience, conscientiousness, extraversion, agreeableness, and emotional stability have gained tremendous prominence in the past two decades. Applications of these frameworks to the study of mass political behavior have been highly fruitful, but corresponding applications in the study of legislators have been rare. In an effort to assess the utility of a Big Five approach in the study of legislative politics, this article addresses three questions: whether elected officials will be willing to provide personality self-assessments, whether any data they do provide will exhibit meaningful variance, and whether the Big Five trait dimensions will correspond with patterns in respondents' attitudes and behaviors. These questions are addressed using data from members of the state legislatures in Arizona, Connecticut, and Maine. Results provide considerable grounds for optimism regarding the likely utility of more extensive applications of the Big Five in research on elected officials.