The withholding of information has a well-established history in psychotherapy. The ability to openly express one's innermost secrets was central to Freud's (1913Freud's ( /1958 psychoanalytic cure and today remains an important component of various forms of psychotherapy. Research findings into the area of withholding information have had important implications for psychotherapeutic development and practice. Similar to psychotherapy research, supervision research findings in this area are likely to have important implications for supervision training and practice. However, our understanding of non-disclosure in clinical supervision is fairly limited at this stage, in comparison with the psychotherapeutic context.Research in the last two decades suggests that supervisors withhold information from their trainees for numerous reasons. Ladany and Melincoff's (1999) study found that 98% of the supervisors withheld critical information from their trainees, citing supervisor uncertainty, concerns it would damage the supervisory relationship and concerns about the mistiming of the disclosures; that is, trainees may not have been developmentally ready to process the non-disclosures. Other reasons for supervisor non-disclosures ranged from anticipated negative reactions from the trainee and withholding information about personal issues, to doubts about their own effectiveness (Heru et al., 2006;Hoffman et al., 2005;Skjerve et al., 2009). Supervisors may also be anxious about their vulnerabilities, which may then prevent them from disclosing to trainees. It has therefore been speculated that they refrain from disclosing their countertransference, not in an attempt to protect trainees, but rather to protect themselves (Frawley-O'Dea & Sarnat, 2001). The effect of these types of non-disclosures on the supervisory process has been largely unaccounted for in supervisory research.