Objectives:
The aim of the study was to prepare the Polish adaptation of the Young Schema Questionnaire S3-PL. The scale is a self-assessment tool designed to measure 18 early maladaptive schemas.

Methods:
The sample consists of 1,529 adults (927 women and 585 men), aged 18–85 years (mean age was 32 years), from non-clinical groups.

Results:
After language validation the internal consistency was assessed. The Cronbach’s alpha ranged from 0.62 (Entitlement/grandiosity) to 0.81 (Failure), and it was 0.96 for total score. The best solution obtained in exploratory factor analysis was an eight-factor model, instead of the assumed 18-factor structure. Confirmatory factor analysis also did not fully supported Young’s theoretical model. From all the tested models, bi-factor model (i.e., one generic factor and correlated specific factors – schemas) fitted the data best. In accordance with this model schema variance is explained concurrently by generic and specific factors; generic factor explains most of the Defectiveness variance, while only slightly – Self-sacrifice variance. Convergent validity analysis confirmes positive medium correlations with scales measuring psychopathology. Similarly, negative correlations with self-efficacy and optimism indicate good divergent validity.

Conclusions:
The psychometric characteristics of the Polish adaptation of the YSQ-S3PL is similar to those reported for other language versions. The results allow to recommend the method for scientific research. However, using it in therapeutic practice needs caution – especially in the case of clinical diagnosis. Further analyses are necessary to assess criterion validity and discriminative power in clinical settings.