Impostor Phenomenon is a pattern of cognitive distortions that involves experiencing feelings of inadequacy or fraudulence that are unwarranted, which may cause psychological effects such as anxiety, depression, burnout, and decreased job satisfaction. There is no previous research on how this phenomenon effects professional music therapists. The purpose of this study was to assess the prevalence of impostor phenomenon among music therapists as a way to understand the well-being of these professionals. A survey was used to assess individual impostor experiences using the Clance Impostor Phenomenon Scale (CIPS). CIPS Scores were analyzed considering various demographics (gender, number of years in the field, level of education, employment situation, additional specialized trainings, and breadth of clientele) using the one-way analysis of variance (ANOVA) to measure whether there was a significant difference between impostor phenomenon scores among the various demographics. A total of 1,132 music therapists participated in the survey and results indicated that the majority of participants experience a moderate level of impostorism. Significant effects were found between impostor phenomenon scores and gender, number of years in the field, level of education, and breadth of clientele seen.