The supervisor-doctoral student interpersonal relationship is important for the success of a PhD-project. Therefore, information about doctoral students' perceptions of their relationship with their supervisor can be useful for providing detailed feedback to supervisors aiming at improving the quality of their supervision. This paper describes the development of the questionnaire on supervisor-doctoral student interaction (QSDI). This questionnaire aims at gathering information about doctoral students' perceptions of the interpersonal style of their supervisor. The QSDI appeared to be a reliable and valid instrument. It can be used in research on the relationship between supervisor and doctoral student and can provide supervisors with feedback on their interpersonal style towards a particular student.