The evaluation of professional supervision has been a focus for discussion in the supervision literature over past decades. A review of the literature in this area, however, suggests that evaluation has been differently defined, variously addressed, and a range of outcomes reported. The present study reports the findings of the first stage of a three-stage study of evaluation in professional supervision in Aotearoa/New Zealand. Experienced practitioners from the four professions of counselling, mental health nursing, psychology, and social work were interviewed to explore how evaluation in professional supervision is understood and actioned in practice. Twenty four semistructured interviews were conducted with supervisees, supervisors, and managers from each of the identified professions. The findings from these interviews indicate that a majority of participants applied some form of evaluation to their supervision arrangement. These evaluations, however, did not reflect an overarching organizational or professional culture of formal evaluation, but rather, an individualized ad-hoc process initiated by one or both of the participants (supervisor and supervisee). These evaluations focussed predominantly on the process, rather than the outcomes, of supervision. While many respondents expressed interest in a formal process for evaluating supervision, a number of concerns were also raised. These concerns included a lack of evaluation skills and resource, the potential for formal evaluation to have a negative impact on the supervision relationship, the importance of maintaining the boundaries of confidentiality, and a wariness regarding the possible use of any information gathered.