This paper describes the development of an instrument--The Reflective Supervisor Questionnaire (RSQ). The RSQ maps the domain of research supervisory practice as a facilitative process involving educational tasks and activities. It is designed to assist research supervisors explore, by means of self-reflection and reflection on feedback from others, how they practise supervision. In developing the RSQ 58 items were generated describing 5 hypothesised constructs derived from prior research. The resulting instrument was tested on postgraduate research students in 2 institutions. The questionnaire correlated highly with an established questionnaire supervision scale and with an overall satisfaction measure. Four factors identified in an exploratory analysis closely approximated the hypothesised constructs and extended the theoretical framework being developed. These 4 factors identified 4 subsets of facilitative supervisory practice: Progressing the Candidature, Mentoring, Coaching the Research Project, and Sponsoring Student Participation in Academic/Professional Practice. Issues in the interpretation of the findings and the possible usage in academic development programs of an instrument based on them are discussed. (Contains 3 tables.)