Recognizing the need for a concise self-report measure of mentalizing capacity, we developed a 12-item iteration of the well-established Mentalization Scale (MentS). Using college student and community samples of Serbian adults (N = 566), we performed a precise selection of items and then examined the psychometric attributes of the shortened scale (MentS-12). The new scale maintains the original three-dimensional structure: self-related mentalization, other-related mentalization, and motivation to mentalize. MentS-12 proves to be both reliable and structurally consistent. To improve its utility in therapeutic contexts, we determined clinical change thresholds for both the complete and abbreviated forms. We hope that its feasibility stimulates the integration of the MentS-12 in longitudinal research projects and real-world clinical settings.