The impostor phenomenon (IP; Clance & Imes, 1978) is a common experience among individuals in the workplace, often occurring without their knowledge. IP describes how an individual can convince themselves they are a ‘fraud’ within the workplace, having ‘faked’ their way to success, in which they fear being exposed as an imposter. Individuals who experience IP often experience mental blocks that impact their competence, affecting their behaviors and performance in the workplace. This study was measured through a time-lagged survey that explores the relationship between IP and creativity within the workplace, using ego depletion as the mediator of that relationship. Results of the study support the hypothesis, showing that IP is positively related to ego depletion, and ego depletion is negatively related to creativity, which ego depletion mediates the relationship between IP and workplace creativity. These findings support the concept that IP can be a resource-draining experience, shown through ego depletion, and that IP is negatively related to workplace creativity. A discussion of these implications for theory and directions for future research will be provided.