Change in self-understanding of maladaptive interpersonal patterns has been an important mechanism of symptom change in theories of dynamic psychotherapy and has been specified as an important treatment outcome by psychotherapy clients. The current investigation evaluated the reliability and validity of a new self-report measure of Self-Understanding of Interpersonal Patterns (SUIP). The measure was administered to 3 clinical samples and a student sample. The measure demonstrated good internal consistency, test-retest reliability, and discriminant validity. The SUIP further demonstrated convergent validity with measures of analytical and self-improving personality traits in a clinical sample. Finally, there was significantly greater change in self-understanding in a dynamic psychotherapy as compared with a medication treatment condition, despite comparable symptom change across both treatment conditions.