Introduction. Studies consistently show a connection between perfectionism as a multidimensional construct with various psychological and psychopathological states and characteristics. However, studies that analyze the connection between this concept and sleep disturbances, especially modalities of insomnia, are rare. Objective. The aim of this study was to examine whether dimensions of perfectionism can explain different forms of insomnia; difficulties initiating sleep (insomnia early), difficulties during the sleep (insomnia middle), waking in early hours of the morning (insomnia late) and dissatisfaction with sleep quality (subjective insomnia). Methods. The sample consisted of 254 students of the School of Medicine in Belgrade. Predictive significance of nine perfectionism dimensions, measured by Frost’s and Hewitt’s and Flett’s scales of multi-dimensional perfectionism, related to four modalities of insomnia, measured by a structured questionnaire, was analyzed by multiple linear regression method. Results. Perfectionism dimensions are significant predictors of each of the tested forms of insomnia. Doubt about actions significantly predicts initial insomnia; to other-oriented perfectionism in the negative pole and socially prescribed perfectionism underlie the difficulties during the sleep, while organization and parental criticism underlie late insomnia. Significant predictors of subjective insomnia are personal standards and organization and to other-oriented perfectionism on the negative pole. Three of nine analyzed dimensions were not confirmed as significant; concern over mistakes, parental expectations and self-oriented perfectionism. Conclusion. Various aspects of perfectionism can be considered as a vulnerability factor for understanding some forms of insomnia. Out of all forms of insomnia tested, perfectionism as the personality trait proved to be the most significant for understanding subjective insomnia.