Objective: This study aimed to develop and validate a new measure- the Adolescent Strengths Use Scale- to assess school-based strength use among Turkish adolescents. Method The study group consisted 1209 Turkish students in grades 7-12. A 12-item pool was initially created in light of the relevant literature and content analysis of open-ended questions asked to the relevant stakeholders including students, parents, teachers and psychological counsellors. Then, 16 experts evaluated the items in terms of their scope, conformity with language, and compliance with measurement and evaluation principles. The expert evaluation resulted in 7 remaining items which were subsequently tested with a pilot study (n = 103 students). n Results Exploratory factor analysis (n = 596 students) yielded a single factor structure that explained 49.4% of the total variance. Confirmatory factor analysis (n = 376) provided a good model fit to the data: X[superscript 2]/df = 2.52, p < 0.001, TLI = 0.96, CFI = 0.98, GFI = 0.97, and RMSEA = 0.06. Regarding criterion validity, the scale had a significant positive correlation with student subjective well-being and prosociality while it had negative significant correlations with symptoms of internalising and externalising behaviours. Furthermore, the scale produced strong internal reliability estimates ([Alpha] = 0,82, [Omega] = 0,83).The test-retest result was also sufficient (r = 0,88). Conclusions: The results suggest that the newly developed scale can be used as a reliable and valid assessment tool to measure adolescents' strength use in school settings.