Psychology-specific epistemological beliefs (EBs) are believed to influence students' approach to and performance in psychology courses. However, empirical research on this topic is limited due in part to a lack of well-validated instruments measuring this construct. The primary objective of this research was to develop and validate the Psychology-Specific Epistemological Belief Scale (Psych-SEBS), a short self-report instrument measuring psychology-specific EBs. Study 1 addresses the structural validity, internal consistency, test-retest reliability, and convergent validity of the Psych-SEBS. Study 2 addresses the criterion-related and incremental validity of the Psych-SEBS. Findings indicated acceptable psychometric properties of this 13-item instrument and its three subscales, namely, significance of psychology research, subjective nature of psychology knowledge, and predictability of human behavior. Scores on Psych-SEBS scales were significantly associated with construct-relevant outcomes, including student interest and performance in psychology courses, and explained unique variance in these outcomes beyond that explained by existing instruments.