Clinical Psychometrics can be defined as a discipline that deals with the definition and measurement of clinical constructs. Among its interests, it includes dimensions, such as skills, behavior, psychopathology, quality of life, and personality. Indeed, this discipline focuses on individual differences, the theory of measurement, the construction of measure instruments and their application in an international context. Clinical Psychometrics can be considered as an essential tool in many fields of research related to psychological and psychiatric interventions: for example, it is useful for diagnostic assessment (in various fields, including clinical and forensic areas), for the design and evaluation of specific psychological and pharmacological treatments. Therefore, Clinical Psychometrics is an applied discipline using psychometric tools to develop evidence-based type procedures relating to the understanding and improvement of the psychological conditions of individuals. This Research Topic on “Clinical Psychometrics” is interested in several aspects of measurement of psychological variables, focusing on the two fundamental paradigmatic aspects of the discipline, the Classical Test Theory and the Item Response Theory. This Research Topic seeks to stimulate a scientific debate between psychotherapists and psychometricians in this area. It could have applicative fallouts, such as designing trans-cultural studies in order to: 1) investigate the invariance of new instruments for measuring clinical variables; 2) test the invariance of existing instruments used in clinical research; 3) develop more refined measure instruments for the evaluation of clinical dimensions, similarly to work conducted by the Obsessive Compulsive Cognitions Working Group in identifying domains considered central to OCD and developing the 87-item Obsessive Beliefs Questionnaire; 4) evaluate therapeutic outcomes and processes (such as, states stress, psychological distress, psychological adjustment to illness, health-related quality of life, mood disorders, sexual functioning, etc.). The goal of this Research Topic is to disseminate a culture of integration between “psychometric model” and “clinical model”, promoting the scientific debate about the deepening of the existing methods and/or the proposal of new methods capable of combining clinical significance with quantitative rigor. This Research Topic welcomed all types of articles, with the exception of case reports. We were particularly interested in: 1. Systematic reviews shedding new lights on the psychometric properties of the most used psychological measures in clinical psychology, neuroscience, psychiatry, psychosomatics, etc.; 2. Guidelines and suggestions on the correct use and gold standards in psychological assessment in the form of research studies and brief reports on the development of new measures and adaptation of existing ones.