The model for interpersonal teacher behavior, mapping the various teachers' interpersonal behaviors, has been applied for research in many countries. In order to measure the students' perceptions regarding the interaction with their teachers, the Questionnaire on Teacher Interaction (QTI) has been developed. The QTI has been shown to be a valid and reliable instrument in all the different language versions in which it was adapted. Translated and validated in many countries, the QTI has not yet received a validation in Italy. The present study was conducted on a population of Italian secondary school students with the aim to examine the psychometric properties of the Italian translation of the QTI in its 64-item version. Results show that individual and class-mean reliabilities and the values related to the scales' ability to differentiate between classrooms are in line with those of the original research and of the other validation studies. Moreover, the circumplex nature of the octagonal model of the QTI is confirmed by the interscale correlations. Finally, results show that the more positive are the QTI dimensions of affiliation and control, the more positive are students' academic achievement and learning motivation.