The impostor phenomenon (IP) is characterised by a belief that one is not actually intelligent or accomplished, despite objective evidence of success, but rather has fooled others and is therefore vulnerable to discovery as a fraud. Impostor feelings are widespread in the post-secondary population and may be disproportionately experienced by groups already marginalised within academia (e.g., women, racialised students). The IP may be associated with significant mental health issues and changes long-term education and career plans; as such, it is imperative that administrators take steps to address impostorism on university and college campuses. The purpose of this review was to summarise factors of the IP from existing research on the experiences and background characteristics of undergraduate, graduate and professional students (i.e., medicine, law). Findings on the subject of IP and gender as well as IP and ethnicity were inconsistent. Most studies found that IP was negatively related to self-esteem and various dimensions of mental health. The relationship of IP to grade point average was inconsistent but several studies showed a negative association between IP and measures of academic performance. These findings suggest there is a critical need to bring awareness to and address experiences of the IP in the academic community; implications for campus mental health professionals are explored. Limitations of existing research are addressed and directions for future research are discussed.