The impostor phenomenon is an intense feeling of intellectual and professional fraudulence, which is felt by high-achieving individuals, who may be present in the workplace. Thus, companies should be aware of the impostor phenomenon and its implications to the workforce. Currently, globalization is providing an increased employment opportunities abroad, which have been growing steadily in recent years. Many companies and their human resource departments are growing more aware of this global shift and have increased implementation strategies to accommodate international workers, such as, Self-Initiated Expatriates (SIEs), who voluntarily moved to another country for work. However, despite the prevalence of SIEs in the work place, little is known about interrelated factors that may link the SIEs to the impostor phenomenon. The challenges that SIEs experience, when they initially undergo the expatriation process, may stem from international, individual or impostor phenomenon related factors, such as, education, accent, gender, identity, anxiety and/or fear. Therefore, the aim of the thesis is to explore how do SIEs perceive the challenges of expatriation and whether certain factors relate to the impostor phenomenon. Additionally, it is of interest to investigate how could firms support international workers to mitigate the challenges of expatriation and the impostor phenomenon. Hence, the findings of the research showed and implied that factors, such as, expatriation, international factors, individual factors and impostor phenomenon factors have linkages and interrelated themes. Suggesting that international upbringing, foreign education and language or accent may be a contributing factor to the impostor phenomenon. Since firms and human resource departments are interested in obtaining and maintaining a satisfactory work environment for international workers, this thesis provides a recommendation for mitigating the challenges of expatriation and the impostor phenomenon, by implementing increased feedback, supporting network groups and providing on-board training for international workers.