Most research on adult attachment is based on the assumption that working models are relatively general and trait-like. Recent research, however, suggests that people develop attachment representations that are relationship-specific, leading people to hold distinct working models in different relationships. The authors report a measure, the Relationship Structures questionnaire of the Experiences in Close Relationships-Revised (ECR-RS; R. C. Fraley, N. G. Waller, & K. A. Brennan, 2000), that is designed to assess attachment dimensions in multiple contexts. Based on a sample of over 21,000 individuals studied online, it is shown that ECR-RS scores are reliable and have a structure similar to those produced by other measures. In Study 2 (N = 388), it is shown that relationship-specific measures of attachment generally predict intra- and interpersonal outcomes better than broader attachment measures but that broader measures predict personality traits better than relationship-specific measures. Moreover, it is demonstrated that differentiation in working models is not related to psychological outcomes independently of mean levels of security.