The interpersonal circumplex (IPC) is a well-established model of social behavior that spans basic personality and clinical science. Although several measures are available to assess interpersonal functioning (e.g., motives, traits) within an IPC framework, researchers studying interpersonal difficulties have relied primarily on a single measure, the Inventory of Interpersonal Problems—Circumplex Scales (IIP-C; Horowitz, Alden, Wiggins, & Pincus, 2000). Although the IIP-C is a widely used measure, it is currently the only measure specifically designed to assess maladaptive interpersonal behavior using the IPC framework. The purpose of the current study is to describe a new 64-item measure of interpersonal problems, called the Circumplex Scales of Interpersonal Problems (CSIP). Interpersonal problems derived from a pool of 400 personality-related problems were assessed in two large university samples. In the scale development sample (N = 1,197), items that best characterized each sector of the IPC were identified, and a set of eight 8-item circumplex scales was developed. Psychometric properties of the resulting measure were then examined in the validation sample (N = 757). Results from confirmatory circumplex structural analyses indicated that the CSIP fit well to a quasi-circumplex model. The CSIP converged with the IIP-C and the Revised Interpersonal Adjective Scales (Wiggins, 1995), and associated in theoretically expected ways with broader assessments of adaptive- and maladaptive-range personality traits and symptoms of psychological distress. The CSIP augments the IIP-C with additional content, thereby helping to extend the underlying constructs, and provides an alternative means for studying the interpersonal consequences of personality and psychopathology.