Guided Imagery and Music (GIM) is a unique method of psychotherapy that uses music and spontaneous imagery while the client is in a non-ordinary state of consciousness (NOSC). Therapists in any therapeutic modality including GIM have a wide range of unanticipated reactions to clients' experiences. Studies have indicated that reactions of the therapist can lead to different interventions and can impact the outcome of the session and perceived effectiveness as a therapist. Because GIM therapists often work with clients who have extensive emotional and physical issues, it is possible that the therapists have strong reactions to clients’ experiences, which can lead to burnout. The purpose of this study, therefore, was to explore therapists’ experience of unanticipated reactions through the within-case and cross-case analysis using phenomenology outlined by Moustakas (1994). Findings suggested that the GIM therapist had certain expectations in GIM and it was normal for the GIM therapist to have unanticipated reactions to clients' experiences when those expectations were not met. There were several factors that affected the decision-making of GIM therapists after unanticipated reactions, including self-mediation, cognitive foundation, self-awareness, therapist's past experiences, trust, surrender, being present, integration, and self-care. Findings also suggested that GIM therapists could deal with unanticipated reactions within the scope of practice as they engage in personal-growth, self-care, and continuing education. Two guidelines were proposed to understand the process of GIM therapists in their moments of unanticipated reactions. Limitations and implications for further studies were discussed. / Music Therapy