From the existing self-report measures for youth Obsessive–Compulsive (OC) symptoms, several challenges can be delineated to further improve the assessment of youth OC-related pathology. The current manuscript incorporates these challenges and reports on the development and validation of a new self-report OC scale for younger age groups, that was labeled the Youth Obsessive–Compulsive Symptoms Scale (YOCSS), assessing OC symptoms and impairment in adolescents (three independent samples: N = 336; N = 289; and N = 209). Study 1 reports on the construction of the items and facets, and their higher-order structure, whereas Study 2 focuses on the confirmation of this structure, measurement invariance across age, and on the convergent and incremental predictive validity. These psychometric analyses resulted in ten symptom facets (structured in three domains) and one impairment facet, and further suggest that the YOCSS is a promising tool for describing early OC symptoms along a dimensional perspective.