Impostor syndrome is a psychological phenomenon in which an individual, despite achievements and external success, believes that his success was achieved by fraud, that is, that success is the product of mere luck, manipulation of other people, or more effort and work that they put in than what people normally put in. The aim of this research was to examine the degree of expression of impostor syndrome in psychology students and to examine certain predictors of the expression of impostor syndrome (gender, year of study, grade point average, negative perfectionism, self-handicapping, and achievement goals). The research was conducted using an online questionnaire on a sample of 326 students (84.36% female students) from various psychology faculties in Croatia. The results indicate a high degree of expression of impostor syndrome. The predictors of the grade average of the previous semester and the grade average from all the previous semesters combined and the mastery-approach goals and avoiding work showed an insignificant correlation with the criterion for the expression of impostor syndrome. By combining other predictors (gender, year of study, negative perfectionism, self-handicapping, mastery-avoidance goals, performance-approach goals, and performance-avoidance goals) in the second step of the hierarchical regression analysis, 65.42% of the variance in the expression of impostor syndrome was explained. The predictors of gender, year of study, and self-handicapping proved to be statistically insignificant; the predictors of negative perfectionism, mastery-avoidance goals, and performance-avoidance goals proved to be statistically significant and positive; and the predictor of performance-approach goals was statistically significant and negative. The obtained results should be more studied to reduce impostor syndrome and its negative impact on students.