Given that at least half of supervisees (therapist trainees) never have their clinical work monitored or observed, supervisees who withhold salient information in clinical supervision compromise supervisors’ ability to monitor client welfare and promote supervisees’ professional development. Attempting to further understand the factors explaining supervisee nondisclosure, we tested the supervisory working alliance as a mediator of the hypothesized inverse relations of cultural humility and collaborative supervision with supervisee nondisclosure (supervision-related and clinically-related nondisclosure) among a diverse sample of 214 supervisees in applied psychology and allied mental health programs. Results supported the hypotheses that (a) descriptively, supervision-related nondisclosure was more prominent than clinically-related nondisclosure; (b) cultural humility substantially inversely predicted supervisee nondisclosure; and (c) the supervisory working alliance fully mediated the inverse relations of cultural humility and collaborative supervision with supervisee nondisclosure. Understanding the mechanisms underlying supervisee nondisclosure has broad implications for clinicians and researchers alike.

Supervisees’ experiences in supervision vary remarkably. To capture such variability, Ellis and colleagues offered a framework for understanding and assessing inadequate, harmful, and exceptional supervision. Although their framework was supported, it did not offer a nuanced understanding of these supervision experiences. Using consensual qualitative research–modified, this study sought to obtain a rich description of inadequate, harmful, and exceptional supervision. Participants ( N = 135) were presented with definitions and provided responses ( n = 156) to open-ended questions describing their inadequate ( n = 63), harmful ( n = 30), and/or exceptional ( n = 63) supervision experiences. Supervisees reporting harmful experiences described supervisors as neglectful and callous, whereas inadequate supervision reflected inappropriate feedback, unavailability, and unresponsiveness. Conversely, exceptional supervision involved safety, clinical paradigm shifts, and modeling specific techniques or theories. Implications for supervision research, theory, and practice are discussed.