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. Need-supportive 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, theory-driven instrument. Its cross-cultural validation supports its use in international contexts, with important implications for research, teacher training, and interventions to promote student well-being.