Perfectionism and the Impostor Phenomenon (IP) have mainly been studied in American samples, as have the associations of Perfectionism and the Impostor Phenomenon with Self-Esteem and the Big Five personality traits. However, previous studies showed that results might depend on cultural background. There is a critical lack of such research in the Russian context which might limit generalization of the previous findings to a narrow range of cultures. In this study, the authors investigated how Perfectionism and the Impostor Phenomenon are related to the 5-factor model of personality, and examined the mediating role of Self-esteem between the dimensions of Perfectionism and the Impostor Phenomenon, using a Russian sample. The study sample comprised 372 undergraduate students age 18-23 (M = 19.07, SD = 1.05). The Impostor Phenomenon, Personality Traits, and Self-Esteem were measured by relevant questionnaires. The results indicated that Adaptive Perfectionism had a strong positive correlation with Extraversion, Conscientiousness, and Openness. Maladaptive Perfectionism had a strong relation to Conscientiousness and Neuroticism. Neuroticism demonstrated a strong positive correlation with impostor tendencies and was the main predictor. Self-esteem partially mediated the link between Maladaptive Perfectionism and the Impostor Phenomenon, intensifying negative feelings and Impostorism. These results generally replicated the pattern from previous studies of the relationship between Perfectionism, the Big Five personality traits, Self-esteem, and the Impostor Phenomenon. Thus, it could be possible to conclude that the studied relationships might be regarded as universal for the Russian students in terms of culture.