Relational self-construal is characterized as the extent to which a person defines the self in terms of close relationships. In this article, I distinguish relational self-construal from collective-interdependent self-construal and from other similar-sounding constructs. I review the history of the concept of relational self-construal and how it is most frequently measured or manipulated. The remainder of the article focuses on research that examines the role of relational self-construal in cognition, affect, motivation, and close interpersonal relationships.