Measuring Teachers’ Motivational Styles: Development and Validation of a Self-Determination Theory-Based Questionnaire in a Dual-Country Study

Grounded in Self-Determination Theory (SDT), this study proposes the Teachers’ Motivational Styles (TMS) questionnaire, a new tool designed to assess how teachers support or frustrate students’ basic psychological needs. Items were developed based on a recent SDT-based taxonomy of need-supportive and need-thwarting teaching behaviors. The questionnaire was administered to 2454 secondary school students in Italy and the United Kingdom. Exploratory Structural Equation Modeling supported a bifactor structure with two general factors—Need Support and Need Frustration—and three specific factors for autonomy, competence, and relatedness. Measurement invariance confirmed the tool’s robustness across countries. Needsupportive teaching predicted higher Positive Affect, lower Negative Affect, and lower Intention to Drop out of school. In contrast, need-frustrating teaching styles predicted increased negative affect and greater risk of school disengagement. The TMS is a psychometrically sound, theorydriven instrument. Its cross-cultural validation supports its use in international contexts, with important implications for research, teacher training, and interventions to promote student wellbeing.