The Polish Temperament Styles Questionnaire (PTSQ), derived from Student Style Questionnaire (SSQ) was developed to measure four bipolar temperament styles: extroverted versus introverted, practical versus imaginative, thinking versus feeling, and organized versus flexible. The study focuses on factorial validity and measurement invariance (configural, metric, and scalar) across gender and age groups using data from 1,022 students ages 8 to 19. Confirmatory factor analysis (CFA) supports the four factor model, and multigroup confirmatory factor analysis (MGCFA) supports measurement invariance for both age and gender groups.