Imposter phenomenon is defined as a sense of intellectual fraudulence and an inability to internalize success and competency. Although imposter phenomenon has been noted in several populations, literature is sparse that focuses on mental health professionals. In addition, little is known about the relationships between imposter phenomenon, compassion fatigue, and compassion satisfaction for mental health workers. Using a survey design with a convenience sample of 158 mental health workers, this study found that imposter phenomenon was positively associated with compassion fatigue, as well as negatively associated with compassion satisfaction, when controlling for years of work and age. Further, the combination of lower levels of compassion satisfaction and higher levels of burnout predicted higher levels of imposter phenomenon. Implications and preventative measures are discussed.